Changes in access to viral load testing, incidence rates of viral load suppression and rebound following the introduction of the 'universal test and treat' guidelines in Cameroon: A retrospective follow-up analysis.

Cameroon adopted and started implementing in 2016, the 'universal test and treat' (UTT) guidelines to fast-track progress towards the 95-95-95 ambitious targets to end the HIV epidemic. Achieving the third 95 (viral load suppression) is the most desirable target in HIV care. We aimed to evaluate the effectiveness of this novel approach on access to viral load testing (VLT), viral suppression (VLS), and viral load rebound (VLR). A retrospective cohort study was conducted at The Nkongsamba Regional Hospital to compare VLT outcomes between the pre-UTT (2002 to 2015) and the post-UTT (2016 to 2020) periods. We used a data extraction form to collect routine data on adult patients living with HIV. We measured uptake levels of the first and serial VLT and compared the incidence rates of VLS (VL<1000 copies/ml) and viral load rebound (VLR) before and after introducing the UTT approach using Kaplan Meier plots and log-rank tests. Cox regression was used to screen for factors independently associated with VLS and VLR events between the guideline periods. Access to initial VLT increased significantly from 6.11% to 25.56% at 6 months and from 12.00% to 73.75% at 12 months before and after introducing the UTT guidelines respectively. After a total observation time at risk of 17001.63 person-months, the UTT group achieved an incidence rate of 90.36 VLS per 1000 person-months, four-fold higher than the 21.71 VLS per 1000 person-months observed in the pre-UTT group (p<0.0001). After adjusting for confounding, the VLS rate was about 6-fold higher in the UTT group than in the pre-UTT group (adjusted Hazard Rate (aHR) = 5.81 (95% confidence interval (95%CI): 4.43-7.60). The incidence of VLR increased from 12.60 (95%CI: 9.50-16.72) to 19.11 (95%CI: 14.22-25.67) per 1000 person-months before and after the introduction of UTT guidelines respectively. After adjusting, VLR was more than twice as high in the UTT group than in the pre-UTT group (aHR = 2.32, 95%CI: 1.30-4.13). Increased access to initial VLT and higher rates of VLS have been observed but there are concerns that the suppressed viral load may not be durable since the introduction of the UTT policy in this setting.

The effect of the Universal Test and Treat policy uptake on CD4 count testing and incidence of opportunistic infections among people living with HIV infection in Cameroon: a retrospective analysis of routine data.

Background: Cameroon adopted and started implementing in 2016, the 'universal test and treat' (UTT) guidelines to fast-track progress towards the 95-95-95 ambitious targets to end the HIV epidemic. UTT has shown inconsistent results elsewhere and has not yet been assessed in Cameroon. We aimed to evaluate the effectiveness of this novel approach on the quality of care and health outcomes of people living with HIV (PLHIV). Methods: A retrospective cohort design was conducted at The Nkongsamba Regional Hospital, using routine clinical service delivery data to measure uptake levels of UTT and CD4 testing, and to compare the incidence of opportunistic infections (OI) between PLHIV initiated on ART based on the "Universal Test and Treat" strategy and those initiated on ART based on the standard deferred approach between 2002 and 2020. Kaplan Meier plots and log-rank tests were used to compare OI events between the pre-UTT and post-UTT eras. The Cox regression model was used to screen for factors independently associated with the risk of acquisition of OI. Results: The uptake of UTT ranged from 39.1% to 92.8% while baseline CD4 count testing reduced drastically from 89.4% to 0.4% between 2016 to 2020 respectively. The median delay in ART initiation declined significantly from 21 days (IQR: 9 - 113) in the pre-UTT era to the same day of diagnosis (IQR: 0 - 2) in the UTT era (p < 0.001). The incidence of all OI events reported was over five times higher during the UTT era than in the pre-UTT era [aHR = 5.55 (95% CI: 3.18 - 9.69), p < 0.001]. Conclusion: The UTT policy has been effectively rolled out and has contributed to improved access to rapid and immediate ART initiation, but a higher incidence of OIs was observed with a rollback of baseline CD4 testing. We advocate for a return to routine baseline CD4 measurement to identify PLHIV who should benefit from interventions to prevent OIs for optimal outcomes under the UTT approach.

Climate change and altitudinal structuring of malaria vectors in south-western Cameroon: their relation to malaria transmission.

An entomological survey was conducted in Cameroon between October 2004 and September 2005, in nine localities targeted for malaria vector control based on adult productivity and variability. Mosquitoes were collected by human-landing catches (HLCs) and pyrethrum spray catches. A total of 12 500 anophelines were collected and dissected: Anopheles gambiae s.l. (56.86%), An. funestus s.l. (32.57%), An. hancocki (9.38%), and An. nili (1.18%). Applying PCR revealed that specimens of the An. funestus group were An. funestus s.s. and An. gambiae complex were mostly An. melas and An. gambiae s.s. of the M and S molecular forms with the M forms being the most predominant. The natural distribution patterns of Anopheles species were largely determined by altitude with some species having unique environmental tolerance limits. A human blood index (HBI) of 99.05% was recorded. Mean probability of daily survival of the malaria vectors was 0.92, with annual mean life expectancy of 21.9 days and the expectation of infective life was long with a mean of 7.4 days. The high survival rates suggest a high vector potential for the species. This information enhances the development of a more focused and informed vector control intervention.

Elephantiasis of non-filarial origin (podoconiosis) in the highlands of north-western Cameroon.

Lymphoedema, a condition of localized fluid retention, results from a compromised lymphatic system. Although one common cause in the tropics is infection with filarial worms, non-filarial lymphoedema, also known as podoconiosis, has been reported among barefoot farmers in volcanic highland zones of Africa, Central and South America and north-western India. There are conflicting reports on the causes of lymphoedema in the highland regions of Cameroon, where the condition is of great public-health importance. To characterise the focus of lymphoedema in the highlands of the North West province of Cameroon and investigate its real causes, a cross-sectional study was carried out on the adults (aged > or =15 years) living in the communities that fall within the Ndop and Tubah health districts. The subjects, who had to have lived in the study area for at least 10 years, were interviewed, examined clinically, and, when possible, checked for microfilaraemia. The cases of lymphoedema confirmed by ultrasonography and a random sample of the other subjects were also tested for filarial antigenaemia. The interviews, which explored knowledge, attitudes and perceptions (KAP) relating to lymphoedema, revealed that the condition was well known, with each study community having a local name for it. Of the 834 individuals examined clinically, 66 (8.1%) had lymphoedema of the lower limb, with all the clinical stages of this condition represented. None of the 792 individuals examined parasitologically, however, had microfilariae of W. bancrofti (or any other filarial parasite) in their peripheral blood, and only one (0.25%) of the 399 individuals tested for the circulating antigens of W. bancrofti gave a positive result. In addition, none of the 504 mosquitoes caught landing on human bait in the study area and dissected was found to harbour any stage of W. bancrofti. These findings indicate that the elephantiasis seen in the North West province of Cameroon is of non-filarial origin.

Epidemiology of concomitant infections due to Loa loa, Mansonella perstans, and Onchocerca volvulus in rain forest villages of Cameroon.

An epidemiological survey was conducted in 16 remote villages of the rain forest of southern Cameroon to ascertain the prevalence and intensity of three species of filariae: Loa loa, Onchocerca volvulus, and Mansonella perstans. We examined 1458 individuals for blood-dwelling microfilariae and 1255 of these were also for the presence of palpable nodules. All the villages surveyed were found highly endemic for onchocerciasis and mansonellosis with prevalence ranging from 28.44% to 87.17% for O. volvulus and 52.48% to 100% for M. perstans. The intensities of infection were also found high for M. perstans with arithmetic means of microfilaremia ranging from 280.94 to 4947.57 mf/ml. The loiasis prevalence was relatively low with value from 2.22% to 19.23%. Males were found more infected than females for the three species of filariae, and the prevalence and intensities of microfilaremia vary differently in males and females at different ages. The three species of filariae displayed different degrees of association in the inhabitants with a low prevalence of co-occurrence between L. loa/O. volvulus and between L. loa/M. perstans. In contrast, there was a high prevalence of co-occurrence between M. perstans and O. volvulus. The implications of the co-occurrence of the three species of filariae in the populations of these remote villages on the intervention programs based on mass treatment with mectizan are discussed.

The migration and localization of Loa loa infective and fourth-stage larvae in normal and immunosuppressed rodents.

The migration and localization of the human filarial parasite Loa loa in laboratory mice (BALB/c and Swiss) and jirds (Meriones unguiculatus) was investigated. The rodents, either left immunocompetent or immunosuppressed with hydrocortisone, were each inoculated subcutaneously or intraperitoneally with 50 or 200 infective, third-stage larvae (L(3)) of L. loa. Groups of the rodents were killed at various times post-infection, up to day 40, to enable histological studies and permit developing larvae to be recovered. Larvae survived and developed for only 1 week in the immunocompetent rodents but for a mean of 3 weeks in the immunosuppressed. Most of the larvae were found in the subcutaneous tissues (81.9%), peritoneal cavity (14.9%), pleural cavity (1.8%) or the lungs and heart (1.3%) and none was detected in the spleen, kidney, intestine, liver or pancreas. Localization of the larvae appeared unaffected by the site of inoculation, the rodent species or strain, or the dose of L(3) used. The recovery of larvae (as a percentage of the number inoculated) was better among the rodents inoculated with 50 L(3) each than among those given four times as many L(3). The results of the histological studies not only confirmed the presence of larvae in the subcutaneous tissue (72.5%), muscles (11.7%) and peritoneal and pleural cavities (7.8%) of the infected rodents but also revealed worms in the lymphatic vessels of the mesentery and spinal cord (7.3%). These results indicate that most L. loa L(3) inoculated into a mammalian host localize in the cutaneous sites and that only a small proportion of them might migrate, using the lymphatic system, into the internal organs. The observation of migrating L. loa larvae in the lymphatic vessel of the meningeal envelope of the spinal cord, albeit in an experimental host, may explain why, in areas where human loiasis is endemic, neurological manifestations occasionally occur in those with L. loa infections.

Co-endemicity of loiasis and onchocerciasis in the South West Province of Cameroon: implications for mass treatment with ivermectin.

Encephalopathy has been reported in Cameroon in individuals heavily infected with Loa loa microfilariae who were treated with ivermectin against onchocerciasis. Prior to the initiation of the community-directed treatment of onchocerciasis with ivermectin (CDTI) in the South West Province of Cameroon, an epidemiological survey of loiasis was conducted (in July 1998-July 1999) to ascertain the intensity of the disease. Thick blood films were made from 1228 blood samples collected during the day. Rapid epidemiological assessment (REA) of onchocerciasis was conducted among 614 individuals in the Upper Bayang area. Sixteen percent of the population examined were carriers of L. loa microfilariae. More males (20.1%) than females (12.4%) were infected. The community mean microfilaraemias of the different villages were low (< 1100 mf/mL). However, 1 person was found harbouring 174,000 mf/mL of blood and 1% of the study population (12) had microfilaraemia > 8100 mf/mL. Results of the REA of onchocerciasis show that 31.3% of the population investigated in the Upper Bayang area have this disease. These findings show that loiasis and onchocerciasis are co-endemic in the area, but the risk of developing encephalopathy after taking ivermectin is small.