Trimethoprim-Sulfamethoxazole Plus Azithromycin to Prevent Malaria and Sexually Transmitted Infections in Pregnant Women With HIV (PREMISE): A Randomized, Double-Masked, Placebo-Controlled, Phase IIB Clinical Trial.

Background: This trial tested the effectiveness of a novel regimen to prevent malaria and sexually transmitted infections (STIs) among pregnant women with HIV in Cameroon. Our hypothesis was that the addition of azithromycin (AZ) to standard daily trimethoprim-sulfamethoxazole (TMP-SMX) prophylaxis would reduce malaria and STI infection rates at delivery. Methods: Pregnant women with HIV at gestational age <28 weeks were randomized to adjunctive monthly oral AZ 1 g daily or placebo for 3 days and both groups received daily standard oral TMP-SMX through delivery. Primary outcomes were (1) positive peripheral malaria infection by microscopy or polymerase chain reaction and (2) composite bacterial genital STI (Chlamydia trachomatis, Neisseria gonorrhoeae, or syphilis) at delivery. Relative risk and 95% confidence intervals were estimated using 2 × 2 tables with significance as P < .05. Results: Pregnant women with HIV (n = 308) were enrolled between March 2018 and August 2020: 155 women were randomized to TMP-SMX-AZ and 153 women to TMP-SMX-placebo. Groups were similar at baseline and loss to follow up was 3.2%. There was no difference in the proportion with malaria (16.3% in TMP-SMX-AZ vs 13.2% in TMP-SMX; relative risk, 1.24 [95% confidence interval, .71-2.16]) or STI at delivery (4.2% in TMP-SMX-AZ vs 5.8% in TMP-SMX; relative risk, 0.72 [95% confidence interval, .26-2.03]). Adverse birth outcomes were not significantly different, albeit lower in the TMP-SMX-AZ arm (preterm delivery 6.7% vs 10.7% [P = .3]; low birthweight 3.4% vs 5.4% [P = .6]). Conclusions: The addition of monthly azithromycin to daily TMP-SMX prophylaxis in pregnant women living with HIV in Cameroon did not reduce the risk of malaria or bacterial STI at delivery.

Prophylactic effects of probiotic bacterium Latilactobacillus sakei on haematological parameters and cytokine profile of mice infected with Plasmodium berghei ANKA during early malaria infection.

Malaria is a deadly parasitic disease caused a by protozoan parasite of the genus plasmodium. The challenges facing by chemotherapy and vector control couple with the lack of vaccine against malaria necessitate an urgent need for the development of alternative treatment regimens to combat this disease. One possible antimalarial treatment regimen is the use of probiotic bacteria as dietary supplements. Traditionally fermented milk is a rich source of probiotic bacteria that up to date, very few studies have been carried out on their immunoprotective effects against early malaria infection in mice. This study sought to assess the prophylactic activities of a probiotic bacterium Latilactobacillus sakei on malaria and inflammation in Plasmodium berghei infected mice. The probiotic bacterium was isolated from the Fulani's traditionally fermented milk and identified using the sequencing of the 16S r RNA gene. The repository activity of L. sakei on malaria was assessed using the method described by Peters with slight modification. Eighty-four BALB/c mice were randomly divided into two sets of seven groups of six mice each. One set received orally different doses of L. sakei Chloroquine and Sulfadoxine/Pyrimethamine for seven days before infection while the other set received for fourteen days before infection with 0.1 mL of 107Plasmodium berghei. Parasitaemia density, haematological parameters and inflammatory cytokines profile were evaluated. Data were presented as Mean ± SEM and analysed using SPSS version 20.0. The results of this study revealed that L. sakei significantly (p < 0.05) reduced in dose dependent manner parasite load, body weight loss and reduction of body temperature in all the treated mice when compare to untreated mice. Leukocytopenia, thrombocytosis and inflammation were also found to be significantly (p < 0.05) prevented in treated mice as compared to untreated mice. This study suggested that L sakei possesses immunomodulation and protective effects on early malaria infection in Plasmodium berghei mice.

Knowledge, attitude, and adherence to malaria control guidelines and the prevalence of Plasmodium species infection in localities across transmission and ecological zones in Cameroon.

Background: Despite a scale up of control interventions over the years, malaria remains a major public health and economic concern in Cameroon, contributing considerably to hospitalization and deaths. The effectiveness of control strategies depends on the extent of adherence by the population to national guidelines. This study assessed the influence of human knowledge, attitudes, and practices related to malaria and its control on the prevalence of malaria parasite infection, with implications for the elimination of the disease. Methodology: This is a cross-sectional community and hospital-based study, covering the five ecological and three malaria transmission zones in Cameroon. A pre-tested semi-structured questionnaire was used to document socio-demographic and clinical parameters as well as knowledge, attitudes, and practices toward malaria control and management. Consenting participants were screened for malaria parasite with rapid diagnostic test (mRDT) of the peripheral blood. Association between qualitative variables was determined using the chi-square test and logistic regression analysis. Results: A total of 3,360 participants were enrolled, 45.0% (1,513) of whom were mRDT positive, with 14.0% (451/3,216) and 29.6% (951/3,216) having asymptomatic parasitaemia and malaria, respectively. Although most participants knew the cause, symptoms, and control strategies, with 53.6% (1,000/1,867) expertly knowledgeable about malaria overall, only 0.1% (2/1,763) individuals were fully adherent to malaria control measures. Conclusion: The risk of malaria in Cameroon remains high, with the population considerably knowledgeable about the disease but poorly adherent to national malaria control guidelines. Concerted and more effective strategies aimed at improving knowledge about malaria and adherences to control interventions are necessary to ultimately eliminate the disease.

Sub-microscopic Plasmodium falciparum parasitaemia, dihydropteroate synthase (dhps) resistance mutations to sulfadoxine-pyrimethamine, transmission intensity and risk of malaria infection in pregnancy in Mount Cameroon Region.

BACKGROUND: Plasmodium falciparum resistance to intermittent preventive treatment with sulfadoxine-pyrimethamine (IPTp-SP) continues to spread throughout sub-Saharan Africa. This study assessed the occurrence of microscopic and sub-microscopic P. falciparum parasitaemia, dihydropteroate synthase mutations associated with resistance to SP and maternal anaemia in the Mount Cameroon area. METHODS: Consenting pregnant women living in semi-rural and semi-urban/urbanized settings were enrolled in this cross-sectional study. Socio-demographic, antenatal and clinical data were documented. Microscopic and sub-microscopic parasitaemia were diagnosed using peripheral blood microscopy and nested polymerase chain reaction (PCR) respectively. The dhps mutations were genotyped by restriction fragment length polymorphism analysis. The presence of A437G, K540E, and A581G was considered a marker for high-level resistance. Haemoglobin levels and anaemia status were determined. RESULTS: Among the women, the prevalence of microscopic and sub-microscopic P. falciparum infection were 7.7% (67/874) and 18.6% (93/500) respectively. Predictors of microscopic infection were younger age (< 21 years) (AOR = 2.89; 95% CI 1.29-6.46) and semi-rural settings (AOR = 2.27; 95% CI 1.31-3.96). Determinants of sub-microscopic infection were the rainy season (AOR, 3.01; 95% CI 1.77-5.13), primigravidity (AOR = 0.45; 95% CI 0.21-0.94) and regular ITN usage (AOR = 0.49; 95% CI 0.27-0.90). Of the145 P. falciparum isolates genotyped, 66.9% (97) carried mutations associated with resistance to SP; 33.8% (49), 0%, 52.4% (76) and 19.3% (28) for A437G, K540E, A581G and A437G + A581G respectively. The A581G mutation was associated with ≥ 3 SP doses evident only among sub-microscopic parasitaemia (P = 0.027) and multigravidae (P = 0.009). Women with microscopic infection were more likely from semi-rural settings (AOR = 7.09; 95% CI 2.59-19.42), to report history of fever (AOR = 2.6; 95% CI 1.07-6.31), to harbour parasites with double resistant mutations (AOR = 6.65; 95% CI 1.85-23.96) and were less likely to have received 2 SP doses (AOR = 0.29; 95% CI 1.07-6.31). Microscopic infection decreased Hb levels more than sub-microscopic infection. CONCLUSION: The occurrence of sub-microscopic P. falciparum parasites resistant to SP and intense malaria transmission poses persistent risk of malaria infection during pregnancy in the area. ITN usage and monitoring spread of resistance are critical.

Genome-wide association study identifies novel candidate malaria resistance genes in Cameroon.

Recent data suggest that only a small fraction of severe malaria heritability is explained by the totality of genetic markers discovered so far. The extensive genetic diversity within African populations means that significant associations are likely to be found in Africa. In their series of multi-site genome-wide association studies (GWAS) across sub-Saharan Africa, the Malaria Genomic Epidemiology Network (MalariaGEN) observed specific limitations and encouraged country-specific analyses. Here, we present findings of a GWAS of Cameroonian participants that contributed to MalariaGEN projects (n = 1103). We identified protective associations at polymorphisms within the enhancer region of CHST15 [Benjamin-Hochberg false discovery rate (FDR) < 0.02] that are specific to populations of African ancestry, and that tag strong eQTLs of CHST15 in hepatic cells. In-silico functional analysis revealed a signature of epigenetic regulation of CHST15 that is preserved in populations in historically malaria endemic regions, with haplotype analysis revealing a haplotype that is specific to these populations. Association analysis by ethnolinguistic group identified protective associations within SOD2 (FDR < 0.04), a gene previously shown to be significantly induced in pre-asymptomatic malaria patients from Cameroon. Haplotype analysis revealed substantial heterogeneity within the beta-like globin (HBB) gene cluster amongst the major ethnic groups in Cameroon confirming differential malaria pressure and underscoring age-old fine-scale genetic structure within the country. Our findings revealed novel insights in the evolutionary genetics of populations living in Cameroon under malaria pressure with new significant protective loci (CHST15 and SOD2) and emphasized the significant attenuation of genetic association signals by fine-scale genetic structure.

Intermittent preventive treatment with Sulphadoxine-Pyrimethamine (IPTp-SP) is associated with protection against sub-microscopic P. falciparum infection in pregnant women during the low transmission dry season in southwestern Cameroon: A Semi - longitudinal study.

The current guidelines for malaria prevention and control during pregnancy in Africa is predicated on the prevention of infection and/or disease through intermittent preventive treatment in pregnancy (IPTp), insecticide-treated nets (ITNs) and effective malaria case diagnosis and management. Concerns that increasing SP resistance in some areas of SSA may have compromised IPTp-SP efficacy prompted this contemporaneous study, designed to assess the prevalence and risk factors of sub-microscopic infection in parturient women during the low transmission season in Mutengene, a rapidly growing semi-urban area in Southwest Region, Cameroon. Pregnant women originally reporting for the establishment of antenatal clinic care during the dry season were followed-up to term and their pregnancy outcomes recorded. About 2 ml of venous blood was collected for malaria diagnosis using PfHRP2/pLDH malaria rapid diagnostic kit and light microscopy. DNA was extracted from dried blood spots by the Chelex-100 method and the Plasmodium falciparum status detected by nested PCR amplification of the 18SrRNA gene using specific predesigned primers. Of the 300 women enrolled, the proportion of malaria parasite infected as determined by microscopy, RDT and PCR was 12.9%, 16.4% and 29.4% respectively, with 39.9% overall infected with P. falciparum by microscopy and/or RDT and/or PCR and a very low-density infection, averaging 271 parasites per microliter of blood. About 25.0% (68/272) of women who were negative by microscopy were positive by PCR (submicroscopic P. falciparum infection), with primigravidae and IPTp-SP non usage identified as independent risk factors for submicroscopic P. falciparum parasitaemia while fever history (aOR = 4.83, 95% CI = 1.28-18.22, p = 0.020) was associated with risk of malaria parasite infection overall. IPTp-SP use (p = 0.007) and dosage (p = 0.005) significantly influenced whether or not the participant will be malaria parasite negative or carry submicroscopic or microscopic infection. Although Infant birthweight and APGAR score were independent of the mother's P. falciparum infection and submicroscopic status, infant's birthweight varied with the gravidity status (p = 0.001) of the mother, with significantly lower birthweight neonates born to primigravidae compared to secundigravidae (p = 0.001) and multigravidae (p = 0.003). Even in holo-endemic dry season, there exists a large proportion of pregnant women with very low density parasitaemia. IPTp-SP seems to be relevant in controlling submicroscopic P. falciparum infections, which remains common in pregnant women, and are hard to diagnose, with potentially deleterious consequences for maternal and fetal health. Future studies should be carried out in hyperendemic malaria foci where the parasitemia levels are substantially higher in order to confirm the efficacy of IPTp-SP.

Diversity and behavioral activity of Anopheles mosquitoes on the slopes of Mount Cameroon.

BACKGROUND: Malaria remains endemic in Cameroon, with heterogeneous transmission related to eco-climatic variations, vector diversity and spatial distribution. The intensification of malaria prevention and control through the free distribution of insecticide-treated nets in recent years may have altered the composition, geographic distribution and natural infection rate of Anopheles species, with implications for malaria transmission dynamics. The present study seeks to assess the vectorial diversity, dynamics and infectivity across different seasons and altitudes in relationship to parasite prevalence around the slopes of Mount Cameroon, southwestern region. METHOD: Mosquitoes were sampled (indoors and outdoors) in 11 eco-epidemiological settings at low (18-197 m), intermediate (371-584 m) and high (740-1067 m) altitude by nightly human landing catches. The mosquitoes were identified morphologically and Anopheles gambiae sibling species identified by PCR. Parity status was ascertained by examining the ovaries and the entomological inoculation rates (EIR) determined by Plasmodium falciparum circumsporozoite antigen ELISA of the head-thorax. The prevalence of Plasmodium infection across target communities was assessed using rapid diagnostic tests. RESULTS: A total of 7327 (18.0 mosquitoes/trap/night) mosquitoes were trapped, mainly during the rainy season (5678, 77.5%) and at low altitude (3669, 50.1%). Anopheles spp. (5079, 69.3%) was the most abundant genera and An. gambiae complex (2691, 36.7%) the major vector, varying with altitude (χ2 = 183.87, df = 8, P < 0.001) and season (χ2 = 28.14, df = 4, P < 0.001). Only An. gambiae (s.s.) was identified following molecular analysis of An. gambiae complex siblings. The overall biting peak for An. gambiae complex was 2-3 a.m. Anopheles cinctus was the most abundant secondary vector in the area. The average EIR in the area was 2.08 infective bites per person per night (ib/p/n), higher at low (2.45 ib/p/n) than at intermediate altitude (1.39 ib/p/n) and during the rainy (1.76 ib/p/n) compared to the dry season (0.34 ib/p/n). Anopheles funestus was most infectious overall (28.1%, 16/57) while An. gambiae had the highest inoculation rates averaging 1.33 ib/p/n. Most Anopheles species across all altitudes and seasons were parous, highest in communities with the highest proportion of malaria parasite infections. CONCLUSION: Anopheles gambiae (s.s.) remains the major malaria vector in the area and An. cinctus possibly a secondary vector of the disease in the slopes of Mt. Cameroon. The seasonal and altitudinal effects on the distribution of these mosquitoes may have implications for the transmission of malaria and its control strategies in the area. Regular monitoring of the bionomics of local Anopheles vector species and targeted control interventions in the 'hotspots' is necessary to curb the prevalence of the infection and incidence of disease.

In vivo antimalarial activity of a probiotic bacterium Lactobacillus sakei isolated from traditionally fermented milk in BALB/c mice infected with Plasmodium berghei ANKA.

ETHNOPHARMACOLOGICAL RELEVANCE: Milk production, processing and consumption are integral part of traditional practices in Fulani tribe of Cameroon. It has been observed that Fulani are resistant to malaria. Dairy products traditionally processed by Fulani are intensively used in the ritual treatment of malarial, inflammations and behavioural disorders. Many studies have demonstrated that fermented milk is a rich source of probiotic bacteria. However, the antimalarial activity of probiotics isolated from this natural source has not been experimentally tested. AIM OF THE STUDY: Hence, this study was therefore aimed at evaluating the antimalarial activity of a probiotic bacterium Lactobacillus sakei isolated from traditionally fermented milk in mice infected with chloroquine sensitive Plasmodium berghei ANKA. MATERIALS AND METHODS: The probiotic bacterium was isolated from the Cameroonian Mborro Fulani's traditionally fermented milk and identified using the 16S r RNA gene sequencing. The schizontocidal activity of Lactobacillus sakei on established malaria infection was evaluated. Eighty-four healthy young adult Balb/c mice infected with Plasmodium berghei parasite were randomly divided into two sets of seven group of six mice each, and were given three different doses of Lactobacillus sakei, chloroquine and sulfadoxine/pyrimethamine for seven and fourteen days respectively. The level of parasitaemia, body temperature, survival time and haematological parameters were evaluated. RESULTS: The parasite growth inhibition was observed to increase with increasing dose of probiotic bacterium with maximum suppression being 100 % at dose 3 on day 20. Also, the probiotic bacterium significantly prevented body weight loss and was associated with body temperature reduction and prevented (p<0.05) a decrease in haematological parameters compared to that untreated malaria infected mice. CONCLUSION: The results obtained suggest that Lactobacillus sakei is a probiotic bacterium with antimalarial activity in mice infected with chloroquine sensitive Plasmodium berghei.

Comparison of conventional and non-invasive diagnostic tools for detecting Plasmodium falciparum infection in southwestern Cameroon: a cross-sectional study.

BACKGROUND: Malaria remains a significant health challenge in sub-Saharan Africa, with early diagnosis critical to reducing its morbidity and mortality. Despite the increasing Plasmodium spp. diagnostic capabilities, access to testing is limited in some cases by the almost absolute requirement for blood from potentially infected subjects as the only sample source for all conventional methods. A rapid test on non-invasive specimen with comparable performance to microscopy for the screening or diagnosis of all participants is invaluable. This study sought to compare conventional and non-invasive diagnostic tools for detecting Plasmodium falciparum. METHODS: This was a cross-sectional study, carried out between March and August 2019 to evaluate and compare the diagnostic performance of a PfHRP2/pLDH-based malaria rapid diagnostic test (mRDT) on patients' blood, saliva and urine relative to conventional light microscopy and nested PCR at outpatient clinics in the Buea and Tiko health districts of Southwestern Cameroon. The significance of differences in proportions was explored using the Pearson's χ2 test whereas differences in group means were assessed using analyses of variance. RESULTS: A total of 359 individuals of both sexes, aged 1-92 years, were enrolled into the study. Of the 301 individuals tested by light microscopy and mRDTs on blood, saliva and urine, 84 (27.9%), 81 (26.9%), 87 (28.9%) and 107 (35.5%) respectively were positive. However, only 34.3%, 90.5%, 91.4%, 83.9% and 65.4% febrile, light microscopy and mRDT positives on blood, saliva and urine respectively had P. falciparum infection as confirmed by PCR. The sensitivity and specificity of presumptive diagnosis, light microscopy and mRDT on blood, saliva and urine were 86.9% and 19.7%, 77.8% and 96.1%, 75.8% and 96.6%, 74.5% and 93.1%, and 70.7% and 81.8%, respectively. The agreement between mRDT on saliva (k = 0.696) and microscopy (k = 0.766) compared to PCR was good. CONCLUSION: The study highlighted the low performance of presumptive diagnosis, reinforcing the need for parasitological tests prior to antimalarial therapy. The higher PfHRP2/pLDH mRDT parasite detection rates and sensitivity in saliva compared to urine suggests that the former is a practical adjunct to or alternative worth optimising for the routine diagnosis of malaria. Flow chart for diagnosis of P. falciparum infection by light microscopy, rapid diagnostic tests and nested PCR.

Drug resistance markers within an evolving efficacy of anti-malarial drugs in Cameroon: a systematic review and meta-analysis (1998-2020).

BACKGROUND: Malaria remains highly endemic in Cameroon. The rapid emergence and spread of drug resistance was responsible for the change from monotherapies to artemisinin-based combinations. This systematic review and meta-analysis aimed to determine the prevalence and distribution of Plasmodium falciparum drug resistance markers within an evolving efficacy of anti-malarial drugs in Cameroon from January 1998 to August 2020. METHODS: The PRISMA-P and PRISMA statements were adopted in the inclusion of studies on single nucleotide polymorphisms (SNPs) of P. falciparum anti-malarial drug resistance genes (Pfcrt, Pfmdr1, Pfdhfr, Pfdhps, Pfatp6, Pfcytb and Pfk13). The heterogeneity of the included studies was evaluated using the Cochran's Q and I2 statistics. The random effects model was used as standard in the determination of heterogeneity between studies. RESULTS: Out of the 902 records screened, 48 studies were included in this aggregated meta-analysis of molecular data. A total of 18,706 SNPs of the anti-malarial drug resistance genes were genotyped from 47,382 samples which yielded a pooled prevalence of 35.4% (95% CI 29.1-42.3%). Between 1998 and 2020, there was significant decline (P < 0.0001 for all) in key mutants including Pfcrt 76 T (79.9%-43.0%), Pfmdr1 86Y (82.7%-30.5%), Pfdhfr 51I (72.2%-66.9%), Pfdhfr 59R (76.5%-67.8%), Pfdhfr 108 N (80.8%-67.6%). The only exception was Pfdhps 437G which increased over time (30.4%-46.9%, P < 0.0001) and Pfdhps 540E that remained largely unchanged (0.0%-0.4%, P = 0.201). Exploring mutant haplotypes, the study observed a significant increase in the prevalence of Pfcrt CVIET mixed quintuple haplotype from 57.1% in 1998 to 57.9% in 2020 (P < 0.0001). In addition, within the same study period, there was no significant change in the triple Pfdhfr IRN mutant haplotype (66.2% to 67.3%, P = 0.427). The Pfk13 amino acid polymorphisms associated with artemisinin resistance were not detected. CONCLUSIONS: This review reported an overall decline in the prevalence of P. falciparum gene mutations conferring resistance to 4-aminoquinolines and amino alcohols for a period over two decades. Resistance to artemisinins measured by the presence of SNPs in the Pfk13 gene does not seem to be a problem in Cameroon. Systematic review registration PROSPERO CRD42020162620.

Fine scale human genetic structure in three regions of Cameroon reveals episodic diversifying selection.

Inferences from genetic association studies rely largely on the definition and description of the underlying populations that highlight their genetic similarities and differences. The clustering of human populations into subgroups (population structure) can significantly confound disease associations. This study investigated the fine-scale genetic structure within Cameroon that may underlie disparities observed with Cameroonian ethnicities in malaria genome-wide association studies in sub-Saharan Africa. Genotype data of 1073 individuals from three regions and three ethnic groups in Cameroon were analyzed using measures of genetic proximity to ascertain fine-scale genetic structure. Model-based clustering revealed distinct ancestral proportions among the Bantu, Semi-Bantu and Foulbe ethnic groups, while haplotype-based coancestry estimation revealed possible longstanding and ongoing sympatric differentiation among individuals of the Foulbe ethnic group, and their Bantu and Semi-Bantu counterparts. A genome scan found strong selection signatures in the HLA gene region, confirming longstanding knowledge of natural selection on this genomic region in African populations following immense disease pressure. Signatures of selection were also observed in the HBB gene cluster, a genomic region known to be under strong balancing selection in sub-Saharan Africa due to its co-evolution with malaria. This study further supports the role of evolution in shaping genomes of Cameroonian populations and reveals fine-scale hierarchical structure among and within Cameroonian ethnicities that may impact genetic association studies in the country.

Pharmacogenetic considerations in the treatment of co-infections with HIV/AIDS, tuberculosis and malaria in Congolese populations of Central Africa.

BACKGROUND: HIV-infection, tuberculosis and malaria are the big three communicable diseases that plague sub-Saharan Africa. If these diseases occur as co-morbidities they require polypharmacy, which may lead to severe drug-drug-gene interactions and variation in adverse drug reactions, but also in treatment outcomes. Polymorphisms in genes encoding drug-metabolizing enzymes are the major cause of these variations, but such polymorphisms may support the prediction of drug efficacy and toxicity. There is little information on allele frequencies of pharmacogenetic variants of enzymes involved in the metabolism of drugs used to treat HIV-infection, TB and malaria in the Republic of Congo (ROC). The aim of this study was therefore to investigate the occurrence and allele frequencies of 32 pharmacogenetic variants localized in absorption distribution, metabolism and excretion (ADME) and non-ADME genes and to compare the frequencies with population data of Africans and non-Africans derived from the 1000 Genomes Project. RESULTS: We found significant differences in the allele frequencies of many of the variants when comparing the findings from ROC with those of non-African populations. On the other hand, only a few variants showed significant differences in their allele frequencies when comparing ROC with other African populations. In addition, considerable differences in the allele frequencies of the pharmacogenetic variants among the African populations were observed. CONCLUSIONS: The findings contribute to the understanding of pharmacogenetic variants involved in the metabolism of drugs used to treat HIV-infection, TB and malaria in ROC and their diversity in different populations. Such knowledge helps to predict drug efficacy, toxicity and ADRs and to inform individual and population-based decisions.

Coverage and effectiveness of intermittent preventive treatment in pregnancy with sulfadoxine-pyrimethamine (IPTp-SP) on adverse pregnancy outcomes in the Mount Cameroon area, South West Cameroon.

BACKGROUND: Growing concerns about the waning efficacy of IPTp-SP warrants continuous monitoring and evaluation. This study determined coverage of IPTp-SP and compared the effectiveness of the 3-dose to 2-dose regimen on placental malaria (PM) infection and low birth weight (LBW) in the Mount Cameroon area. METHODS: Consenting pregnant women were enrolled consecutively through a cross-sectional survey at delivery at four antenatal clinics, two each from semi-rural and semi-urban settings from November 2016 to December 2017. Reported IPTp-SP use, demographic and antenatal clinic (ANC) data of the mothers and neonate birth weights were documented. Maternal haemoglobin concentration was measured using a haemoglobinometer and PM infection diagnosed by placental blood microscopy. Logistic regression analysis was used to model study outcomes. RESULTS: Among the 465 parturient women enrolled, 47.0% (203), 34.7% (150), 18.3% (79) and 7.1% (33) reported uptake of ≥ 3, 2.1 dose(s) and no SP, respectively. Uptake of ≥ 3 doses varied significantly (p < 0.001) according to type of medical facility, timing of ANC initiation and number of ANC visits. The prevalence of PM was 18.5% where uptake of ≥ 3 SP doses (AOR = 2.36: 95% CI 1.41-4.87), primiparity (AOR = 2.13: 95% CI 1.19-3.81), semi-rural setting (AOR = 1.85: 95% CI 1.12-3.04) increased odds of infection. Also, three or more dosing was associated (p < 0.001) with increased PM density notably among women from semi-urban areas. Compared with third trimester, ANC initiation in the second trimester (AOR: 0.39: 95% CI 0.20-0.74) lower odds of infection. The prevalence of LBW infants was 7.3% and were generally those of anaemic (AOR: 4.6: 95% CI 1.03-20.57) and semi-rural (AOR: 5.29: 95% CI 1.73-16.15) women. Although ≥ 3 (AOR: 0.31: 95% CI 0.11-0.87) and 2 (AOR: 0.32: 95% CI 0.11-0.93) doses of SP was associated with lower odds of LBW, ≥ 3 doses were not associated with additional increase in birth weight nor maternal haemoglobin levels when compared with 2 doses. CONCLUSION: In the Mount Cameroon area, reported uptake of IPTp with ≥ 3 SP doses did not provide observable prophylactic benefits. SP resistance efficacy studies are necessary.

Coverage and usage of insecticide treated nets (ITNs) within households: associated factors and effect on the prevalance of malaria parasitemia in the Mount Cameroon area.

BACKGROUND: Insecticide-treated nets (ITNs) are a widely used tool that has been proven to be effective in the prevention and control of malaria in malaria endemic countries. However, usage varies among households and can greatly affect the benefits of ITNs as a control tool for malaria transmission. This study determined the coverage and usage of ITNS as well as associated factors and the effect of coverage and usage on the prevalence of malaria parasitemia within households in the Mount Cameroon area. METHODS: A cross-sectional survey was conducted between August and September 2014 in six communities within the Mount Cameroon area. Households within the communities were enrolled through multistage sampling and household survey was done using a structured questionnaire. Capillary blood was collected for malaria parasite determination. Data was analysed using SPSS version 20 for windows. Differences in proportions were assessed using the Chi-square test while factors affecting ITNs usage were assessed in multivariate logistic regression at a statistical significance of P ≤ 0.05. RESULTS: A total of 504 households were surveyed, 1564 bed spaces reported while 915(58.5, 95% CI: 56.1-60.9) of the bed spaces had nets and 391(77.6, 95% CI, 74.0-80.2) of the households had at least one bed net. The odds of using ITNs was 2 folds higher (OR = 2.41; 95% CI 1.58-3.69 p = 0.001) and 3 folds higher (OR = 3.149, 95% CI 1.53-6.47 p = 0.002) among houses with 5 to 9 occupants and above 10 occupants respectively when compared to houses with less than 5 occupants. In addition, Individuals living in cement block houses were less likely to use ITNs. Compared to those living in wooden houses (OR = 0.488, 95% CI: 0.269-0.885; p = 0 .018). Rural communities had lower ITN coverage compared to semi-urban communities (p = 0.0001). Increase in ITNs coverage significantly reduces malaria prevalence (correlation - 0.899, p = 0.015). CONCLUSION: Despite the efforts made to scale up ITN distribution so that universal coverage can be attained, coverage remains low. Increasing coverage and putting in place a mechanism to replace torn nets will go a long way reduce the prevalence of malaria parasitemia.

Using a composite adherence tool to assess ART response and risk factors of poor adherence in pregnant and breastfeeding HIV-positive Cameroonian women at 6 and 12 months after initiating option B.

BACKGROUND: Antiretroviral therapy (ART) adherence in preventing HIV mother-to-child transmission in association with virological suppression and risk factors of low adherence in the Cameroon's Option B+ programme are poorly understood. We used a composite adherence score (CAS) to determine adherence and risk factors of poor adherence in association with virological treatment response in HIV-positive pregnant and breastfeeding women who remained in care at 6 and 12 months after initiating ART. METHODS: We prospectively enrolled 268 women after ART initiation between October 2013 and December 2015 from five facilities within the Kumba health district. Adherence at 6 and 12 months were measured using a CAS comprising of a 6-month medication refill record review, a four-item self-reported questionnaires and a 30-day visual analogue scale. Adherence was defined as the sum scores of the three measures and classified as high, moderate and low. Measured adherence levels were compared to virological suppression rates at month 12 and risk factors of poor adherence were determined. RESULTS: At 6 and 12 months, 217 (81.0%) and 185 (69.0%) women were available for adherence evaluation. Respectively. Of those, 128 (59.0%) and 68 (31.4%) had high or moderate adherence as per the CAS tool at month 6, and 116 (62.7%) and 48 (24.9%) at month 12, respectively. Viral loads were assessed in 165 women at months 12, and 92.7% had viral suppression (< 1000 copies/mL). Viral suppression was seen in 100% of women with high, 89.5% with moderate, and 52.9% with low adherence using the CAS tool. Virological treatment failure was significantly associated with low adherence [OR 7.6, (95%CI, 1.8-30.8)]. Risk factors for low adherence were younger age [aOR 3.8, (95%CI, 1.4-10.6)], primary as compared to higher levels of education [aOR 2.7, (95%CI, 1.4-5.2)] and employment in the informal sector compared to unemployment [aOR 1.9, (95%CI,1.0-3.6)]. CONCLUSIONS: During the first year of Option B+ implementation in Cameroon our novel CAS adherence tool was feasible, and useful to discriminate ART adherence levels which correlated with viral suppression. Younger age, less educated and informal sector employed women may need more attention for optimal adherence to reduce the risk of virological failure.

Vitamin D Status and Its Associated Risk Factors among Adults in the Southwest Region of Cameroon.

BACKGROUND: Vitamin D has been shown to exert its actions on the musculoskeletal, gastrointestinal, prostate, renal, endocrine, immune, and cardiovascular systems. Current reported data of hypovitaminosis D reveals a global pandemic, with an estimated one billion people worldwide presenting with hypovitaminosis D. OBJECTIVE: This study aimed at investigating the vitamin D status and its associated risk factors in Cameroonians from the South West Region. METHOD: The study was a community- and hospital-based prospective longitudinal study. It was carried out during the dry and rainy seasons between the months of July and December 2015 in the South West Region of Cameroon involving 372 participants aged 35 years and above. After obtaining informed consent, a structured questionnaire was used to capture demographic data and risk factors of vitamin D deficiency. Blood samples were collected from the volunteer participants in the peak months of the rainy season and dry season, and the serum used to analyse for vitamin D by ELISA and calcium by spectrophotometry. 25(OH)D levels ≥75 nmol/L (≥30 ng/mL) were considered sufficient while levels <75 nmol/L were considered as hypovitaminosis D (insufficiency/deficiency). RESULTS: Hypovitaminosis D (deficiency/insufficiency) was prevalent in 25.8% (96) of the study population, with only 3.2% (12) deficiency and 22.6% (84) insufficiency. There was a significant inverse relationship (r=-0.119, p=0.02) between age and 25(OH)D levels; however, this relationship was not significant when controlled for gender, number of hours spent outdoors, and percentage of body covered. Gender, ethnic origin, percentage of body covered, time spent outdoors, and season did not influence serum vitamin D levels. CONCLUSION: Results of this study suggest that the prevalence of hypovitaminosis D is relatively low in this study population and only age is a risk factor of vitamin D deficiency.

Profile of red blood cell morphologies and causes of anaemia among pregnant women at first clinic visit in the mount Cameroon area: a prospective cross sectional study.

OBJECTIVE: Anaemia is a serious problem in pregnancy in malaria-endemic countries. This study investigated red cell morphologies and possible causes of anaemia among pregnant women at first clinic visit. Venous blood samples from consented women were used to determine haemoglobin (Hb) levels, mean corpuscular volume (MCV) and mean corpuscular haemoglobin (MCH) using an automated haematology analyzer. Malaria parasitaemia was diagnosed by microscopy. Definitions were as follows: anaemia (Hb < 11.0 g/dl), microcytosis (MCV < 78 fl), macrocytosis (MCV > 101 fl), hypochromasia (MCH < 27 pg), microcytic hypochromia or normocytic hypochromia with anaemia [iron deficiency anaemia (IDA)], normocytic normochromia with anaemia in the absence of malaria parasitaemia (physiological anaemia of pregnancy). RESULTS: Of the 279 pregnant women enrolled, 57% had anaemia. Malaria parasitaemia was associated with 23.3% of anaemic cases while 76.7% were non-malaria related. The distribution of red cell alterations was as follows: hypochromasia (32.6%), microcytosis (14.7%) and macrocytosis (1.1%). The co-occurrence of malaria parasitaemia, iron deficiency and anaemia was seen in 23.3% of the women, iron deficiency anaemia only occurred in 35.9% while physiological anaemia of pregnancy was 40.9%. Iron deficiency and physiological anaemia of pregnancy contribute to a greater proportion of anaemia in the study area.

Molecular markers for artemisinin and partner drug resistance in natural Plasmodium falciparum populations following increased insecticide treated net coverage along the slope of mount Cameroon: cross-sectional study.

BACKGROUND: Drug resistance is one of the greatest challenges of malaria control programmes, with the monitoring of parasite resistance to artemisinins or to Artemisinin Combination Therapy (ACT) partner drugs critical to elimination efforts. Markers of resistance to a wide panel of antimalarials were assessed in natural parasite populations from southwestern Cameroon. METHODS: Individuals with asymptomatic parasitaemia or uncomplicated malaria were enrolled through cross-sectional surveys from May 2013 to March 2014 along the slope of mount Cameroon. Plasmodium falciparum malaria parasitaemic blood, screened by light microscopy, was depleted of leucocytes using CF11 cellulose columns and the parasite genotype ascertained by sequencing on the Illumina HiSeq platform. RESULTS: A total of 259 participants were enrolled in this study from three different altitudes. While some alleles associated with drug resistance in pfdhfr, pfmdr1 and pfcrt were highly prevalent, less than 3% of all samples carried mutations in the pfkelch13 gene, none of which were amongst those associated with slow artemisinin parasite clearance rates in Southeast Asia. The most prevalent haplotypes were triple mutants Pfdhfr I 51 R 59 N 108 I 164(99%), pfcrt- C72V73 I 74 E 75 T 76 (47.3%), and single mutants PfdhpsS436 G 437K540A581A613(69%) and Pfmdr1 N86 F 184D1246 (53.2%). CONCLUSIONS: The predominance of the Pf pfcrt CVIET and Pf dhfr IRN triple mutant parasites and absence of pfkelch13 resistance alleles suggest that the amodiaquine and pyrimethamine components of AS-AQ and SP may no longer be effective in their role while chloroquine resistance still persists in southwestern Cameroon.

Resistance to malaria through structural variation of red blood cell invasion receptors.

The malaria parasite Plasmodium falciparum invades human red blood cells by a series of interactions between host and parasite surface proteins. By analyzing genome sequence data from human populations, including 1269 individuals from sub-Saharan Africa, we identify a diverse array of large copy-number variants affecting the host invasion receptor genes GYPA and GYPB We find that a nearby association with severe malaria is explained by a complex structural rearrangement involving the loss of GYPB and gain of two GYPB-A hybrid genes, which encode a serologically distinct blood group antigen known as Dantu. This variant reduces the risk of severe malaria by 40% and has recently increased in frequency in parts of Kenya, yet it appears to be absent from west Africa. These findings link structural variation of red blood cell invasion receptors with natural resistance to severe malaria.

Predictors of the use of interventions to prevent malaria in pregnancy in Cameroon.

BACKGROUND: Malaria in pregnancy is common in sub-Saharan Africa where it contributes to perinatal morbidity and mortality. Use of insecticide-treated bed nets and intermittent preventive therapy with sulfadoxine-pyrimethamine during pregnancy are effective but underutilized interventions to prevent infection. Factors associated with bed net ownership and usage, and use of prophylaxis among recently pregnant women in Cameroon were investigated. METHODS: National data from the 2011 Cameroon Demographic Health Survey was used to identify women with a pregnancy within the previous 5 years. Logistic regression models were created to assess for independent predictors of reported bed net ownership, bed net usage, and the use of malaria prophylaxis medications during pregnancy. RESULTS: Nearly one in two women surveyed had a recent pregnancy (n = 7647). In this group, bed net ownership and usage rates were low (33.7 and 16.9%, respectively); 61.6% used medication for malaria prophylaxis during pregnancy. Bed net ownership and usage were associated with maternal literacy (aOR 1.4 for net usage, 95% CI 1.1-1.8) and the presence of children under age 5 in the home (aOR 2.3 for net usage, 95% CI 1.6-3.3). The use of malaria prophylaxis medication was associated with measures of healthcare access (aOR 17.8, 95% CI 13-24.5 for ≥4 antenatal care visits), higher maternal education (aOR 1.5, 95% CI 1.1-2.1) and maternal literacy (aOR 1.4, 95% CI 1.1-1.7). CONCLUSIONS: Women in Cameroon and their antenatal providers missed many opportunities to prevent malaria in pregnancy. Efforts toward ensuring universal bed net provision, consistent antenatal care and the education of girls are likely to improve birth outcomes attributable to malaria infection.