Prostate cancer knowledge and barriers to screening among men at risk in northern Tanzania: A community-based study.

BACKGROUND: Although prostate cancer (Pca) screening plays important role in early diagnosis and reduction of mortality, Tanzanian men are relatively unscreened. We aimed to investigate Pca knowledge level and barriers to screening among at-risk men in northern Tanzania. METHODS: This community-based survey was conducted in northern Tanzania from May to September 2022, involving men age ≥40 years. Participants were invited by announcing in local churches, mosques, brochures, and social media groups. Participants attended a nearby health facility where survey questionnaires were administered. Knowledge level was measured on the Likert scale and scored as poor (<50 %) or good (≥50 %). RESULTS: A total of 6205 men with a mean age of 60.23 ± 10.98 years were enrolled in the study. Of these, 586 (9.5 %) had ever been screened for Pca. Overall, 1263 men (20.4 %) had good knowledge of Pca. Having health insurance, knowing at least 1 risk factor or symptoms of Pca, and hospital as the source of Pca information were significantly associated with ever being screened. The most common reasons for not being screened were a belief that they are healthy (n = 2983; 53.1 %), that Pca is not a serious disease (n = 3908; 69.6 %), and that digital rectal examination (DRE) as an embarrassing (n = 3634; 64.7 %) or harmful (n = 3047; 54.3 %) procedure. CONCLUSION: Having Pca knowledge, health insurance and hospital source of information were correlated with increased screening. False beliefs about DRE and the seriousness of Pca had negative effects on screening. Increasing community knowledge and universal health coverage would improve uptake of Pca screening.

Transfusion-Transmitted Infections and associated risk factors at the Northern Zone Blood Transfusion Center in Tanzania: A study of blood donors between 2017 and 2019.

BACKGROUND: Blood transfusion saves many people every year that would otherwise have died. The present study aimed to provide an update and insightful information regarding prevalence of the common Transfusion-Transmitted Infections (TTIs) and associated factors among blood donors in Tanzania. METHODS: This was a cross-sectional study involving retrospectively collected data of blood donors from the Tanzania Northern Zone Blood Transfusion Center between 2017 and 2019. Descriptive statistics were performed to describe characteristics of the blood donors. Univariable and multivariable logistic regression analyses were performed to determine association between prevalence of TTIs and socio-demographic factors. P-value <0.05 was considered statistically significant. RESULTS: A total of 101, 616 blood donors were included in the present study of which 85,053(83.7%) were males while 16,563 (16.3%) were females. Of all participants, the majority 45,400 (44.7%) were aged between 18 and 25 years; 79,582 (78.3%) were voluntary non-remunerated donors while 22,034 (21.7%) were replacement donors. The vast majority of them 99,626 (98%) were first time blood donors while 1990 (2%) were multiple donors. The overall prevalence of TTIs was 10.1% (10,226 out of 101,616) of which the leading was HBV accounting for 5.1% (5,264 out of 101,616). Being a replacement donor was associated with all the four types of TTIs: HIV (AOR = 1.22, 95% CI = 1.10-1.35), HBV (AOR = 1.35, 95% CI = 1.27-1.44), HCV (AOR = 1.28, 95% CI = 1.12-1.46), and syphilis (AOR = 1.33, 95% CI = 1.20-1.48). CONCLUSIONS: Our study has demonstrated that Tanzania has relatively high prevalence of TTIs compared to some countries in Sub-Saharan Africa. HBV infection seems to be the most common infection among blood donors and replacement blood donors are at a higher risk of harboring the commonest TTIs among blood donors.

In vitro and in vivo studies on anti-malarial activity of Commiphora africana and Dichrostachys cinerea used by the Maasai in Arusha region, Tanzania.

BACKGROUND: Traditional medicinal plants are one of the potential sources of anti-malarial drugs and there is an increasing interest in the use and development of traditional herbal remedies for the treatment of malaria and other ailments. This study was carried out with the aim to investigate the phytochemical screening, cytotoxic effect and antiplasmodial activities of Dichrostachys cinerea and Commiphora africana. Both plants are used by the Maasai in Tanzania in suspected malaria and other diseases. No previous work appears to have investigated the potential anti-malarial activity of the two plants. METHODS: This study aimed to investigate the in vitro anti-malarial activity of methanol and dichloromethane extracts of the two plants against chloroquine sensitive (D6) and chloroquine resistant (Dd2) strains of Plasmodium falciparum. The anti-malarial property was assessed by the lactate dehydrogenase method (pLDH). The in vivo anti-malarial study was carried out using the Peters' 4-day suppressive test in Plasmodium berghei in Balb/c mice. Cytotoxic tests were carried out using monkey kidney epithelial cell line in [3(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] (MTT) assay. Qualitative phytochemical screening was carried out using standard methods of analysis. RESULTS: The phytochemical screening of plant extracts revealed the presence of alkaloids, flavonoids, tannins, steroids, triterpenoids, glycosides and saponins. However, alkaloids were absent in most plant extracts. The dichloromethane extracts of C. africana (stem bark); D. cinerea (stem bark) and methanol extracts of D. cinerea (whole stem) all showed promising in vitro anti-malarial activities. All other extracts did not show any significant anti-malarial activity. The two most promising extracts based on in vitro studies, DCM extracts of C. africana (stem bark) and D. cinerea (stems bark), equally exhibited very significant anti-malarial activities in the mouse model. They exhibited parasite suppression rates of 64.24 and 53.12%, respectively, and considerable improvement in weight and survival rate. Most plant extracts were not cytotoxic except for DCM extract of D. cinerea (whole stem) CC50 (29.44 µg/mL). CONCLUSION: The findings of this study provide scientific evidence supporting the traditional use of the plants in the treatment of malaria by the Maasai in Arusha region, Tanzania. Consequently, further work including bioassay-guided fractionation and advanced toxicity testing may yield new anti-malarial drug candidates from the two plants.

Prevalence and associated risk factors for Kaposi's sarcoma among HIV-positive patients in a referral hospital in Northern Tanzania: a retrospective hospital-based study.

BACKGROUND: Kaposi's sarcoma (KS) is a multifocal angioproliferative tumor involving blood and lymphatic vessels, caused by Human Herpes Virus-8 (HHV-8). KS is an important AIDS-defining tumor with high prevalence in Sub-Saharan Africa, including Tanzania which has high HIV and HHV-8 sero-prevalence. It is critically important to monitor the prevalence of AIDS-defining tumors, such as KS, in the age of HIV/AIDS. We studied the prevalence of KS and associated risk factors among HIV-positive patients at Kilimanjaro Christian Medical Centre (KCMC), a referral hospital in northern Tanzania, over the period from January 2012 to December 2015. METHODS: This was a retrospective hospital-based cross-sectional study to determine the prevalence of KS among HIV/AIDS patients between 2012 and 2015. The study included 1100 HIV patients' data which were collected at the Infectious Disease Clinic (IDC) from patients' files. Stata version 13 (StataCorp LP, Texas 77,845 USA) was used for all statistical analyses. The prevalence of KS was calculated across levels of a number of categorical variables. Logistic regression was performed to determine relative risk of KS for all characteristics. We included all variables with p-values ≤10% in the multivariate analysis, including ART use, as this is considered to have an influence on KS. In the multivariate analysis, statistical significance was established based on a two-tailed p-value ≤5%. All patients' notes were kept confidential as per the Helsinki declaration. RESULTS: Our results revealed a 4.6% prevalence of KS at KCMC hospital, between January 2012 and December 2015, 51(4.6%) patients were diagnosed with KS out of 1100 HIV-positive patients. The study further revealed that KS in HIV patients was most associated with low CD4 cell count (less than or equal to 200 cells/µl). Moreover, women were more likely than men to diagnosed with KS, with higher odds significantly associated with KS (OR 0.42, p < 0.009). Increased age, above 35 years, among the HIV seropositive patients was significantly associated with KS (OR 25.67, p < 0.007). HIV patients who were none smokers were more likely to suffer from KS compared to HIV smokers (OR 0.41, p < 0.010). CONCLUSION: KS remains a common malignant vascular tumor commonly associated with HIV/AIDS in Tanzania. Our study highlights the need for continued efforts to combat HIV, as well as associated diseases such as KS. Continued availability of ART (Anti-Retroviral Therapy) to HIV/AIDS patients, and test reagents for CD4 cell count and viral load determination are important measures to alleviate the suffering of these patients. Furthermore, studies to gather more evidence on ART resistance are highly needed to guide treatment choices.

Exploring the Role of IL-32 in HIV-Related Kaposi Sarcoma.

The intracellular proinflammatory mediator IL-32 is associated with tumor progression; however, the mechanisms remain unknown. We studied IL-32 mRNA expression as well as expression of other proinflammatory cytokines and mediators, including IL-1α, IL-1ß, IL-6, IL-8, tumor necrosis factor (TNF)-α, the proangiogenic and antiapoptotic enzyme cyclooxygenase-2, the IL-8 receptor C-X-C chemokine receptor (CXCR) 1, and the intracellular kinase focal adhesion kinase-1. The interaction of IL-32 expression with expression of IL-6, TNF-α, IL-8, and cyclooxygenase-2 was also investigated. Biopsy specimens of 11 HIV-related, 7 non-HIV-related Kaposi sarcoma (KS), and 7 normal skin tissues (NSTs) of Dutch origin were analyzed. RNA was isolated from the paraffin material, and gene expression levels of IL-32 α, ß, and γ isoforms, IL1a, IL1b, IL6, IL8, TNFA, PTGS2, CXCR1, and PTK2 were determined using real-time quantitative PCR. Significantly higher expression of IL-32ß and IL-32γ isoforms was observed in HIV-related KS biopsy specimens compared with non-HIV-related KS and NST. The splicing ratio of the IL-32 isoforms showed IL-32γ as the highest expressed isoform, followed by IL-32ß, in HIV-related KS cases compared with non-HIV-related KS and NST. Our data suggest a possible survival mechanism by the splicing of IL-32γ to IL-32ß and also IL-6, IL-8, and CXCR1 signaling pathways to reverse the proapoptotic effect of the IL-32γ isoform, leading to tumor cell survival and thus favoring tumor progression.

Colorectal cancer in a patient with intestinal schistosomiasis: a case report from Kilimanjaro Christian Medical Center Northern Zone Tanzania.

BACKGROUND: Colorectal cancer associated with chronic intestinal schistosomiasis has been linked with the chronic inflammation as a result of schistosomal ova deposition in the submucosal layer of the intestine. Among all species Schistosoma japonicum has been more linked to development of colorectal cancer as compared to Schistosoma mansoni due to absence of population-based studies to support the association. Despite the weak evidence, some cases have been reported associating S. mansoni with development of colorectal cancer. CASE PRESENTATION: We report a patient who presented to us as a case of intestinal obstruction and found to have a constrictive lesion at the sigmoid colon at laparotomy, then later found to have colorectal cancer with deposited S. mansoni ova at histology. CONCLUSION: Given the known late complications of schistosomiasis, and as S. mansoni is endemic in some parts of Tanzania, epidemiological studies are recommended to shed more light on its association with colorectal cancer.

TORCH Antibodies Among Pregnant Women and Their Newborns Receiving Care at Kilimanjaro Christian Medical Centre, Moshi, Tanzania.

BACKGROUND: Toxoplasmosis, other (syphilis, varicella-zoster, parvovirus B19, and hepatitis B), rubella, cytomegalovirus (CMV), and herpes simplex virus type 1 and type 2 (HSV-1 and HSV-2) - known by the acronym TORCH - is a group of infections affecting both mothers and their unborn babies with adverse short- and long-term outcomes. The majority of infected mothers are asymptomatic, which leaves only speculation as to the probable cause of many congenital anomalies, stillbirths, prematurity, and death resulting from TORCH infections. The main objective of this study was to investigate previous exposure to TORCH infections by measuring the seroprevalence of TORCH antibodies in pregnant women and their newborns receiving care at Kilimanjaro Christian Medical Centre (KCMC), Moshi, Tanzania. METHODS: This was a cross-sectional, hospital-based study conducted at KCMC from December 2013 to April 2014. Of 350 pregnant women enrolled in the study, we tested 347 pregnant women attending the antenatal clinic and who opted to deliver at KCMC. Cord blood was collected and analysed for 309 of their newborns. To identify immunoglobulin G (IgG) and immunoglobulin M (IgM) antibodies in mothers and IgM antibodies in newborns, we used enzyme-linked immunosorbent assay testing. A structured questionnaire was used to collect data of mothers and their newborns. Data analysis was done using SPSS version 20. RESULTS: The seroprevalence of IgG antibodies to TORCH infections among pregnant women was 154 (44.4%) for toxoplasmosis, 311 (89.6%) for rubella, 343 (98.6%) for CMV, and 346 (99.7%) for HSV-1 and HSV-2; 141 (40.6%) had been exposed to all 4 infections. For HSV-1 and HSV-2, the IgM antibodies were found in 137 (39.5%) of the 347 pregnant women included in this study. Age above 35 years (OR 6.15; 95% CI, 1.22-31.1; P=.028) and multiparity (OR 1.63; 95% CI, 1.01-2.62; P=.045) were associated with higher risk of being exposed to all TORCH infections. A total of 11 newborns had IgM antibodies to HSV-1 and HSV-2 giving a seroprevalence of 3.6%, and one newborn had IgM antibodies to rubella, giving a seroprevalence of 0.3%. None of the newborns had antibodies to toxoplasmosis and CMV. CONCLUSION: Exposure to TORCH infections was high among pregnant women in our population. Older age and multi-parity were associated with a higher risk of being exposed to all TORCH infections. Seroprevalence to HSV-1 and HSV-2 was high in newborns. The higher IgM antibodies to HSV-1 and HSV-2 among pregnant mothers and their newborns may disturb maternal, fetal, and neonatal health, and therefore we recommend establishing treatment protocol to support management of pregnant women and newborns who are seropositive for IgM antibodies.

Diagnosis of human fascioliasis in Arusha region, northern Tanzania by microscopy and clinical manifestations in patients.

BACKGROUND: Human fascioliasis (HF) is a zoonotic disease that has been identified in many countries worldwide. This report concerns the identification and clinical management of cases of human fascioliasis in the suburbs of Arusha city, northern Tanzania in 2013. Fascioliasis is included among the WHO's Neglected Tropical Diseases as a plant transmitted trematode infection. Human fascioliasis has not been described before in the East Africa region, including Tanzania. METHODS: Patients presenting at a primary healthcare centre in Arusha Region, northern Tanzania provided fresh stool samples for routine ova and parasite screening (saline and iodine preparations). Subsequent stool samples were preserved in 5 % formalin in saline and subjected to ether sedimentation for examination. RESULTS: Out of 1460 patients, 305 (21 %) were diagnosed positive for fascioliasis based on the demonstration of brownish, oval eggs with inconspicuous opercula in stool. Two distinct egg sizes were identified; large 170-212.5 by 115-150 µm (mean 194.5 by 130.5 µm) and smaller eggs 120-150 by 87.5 - 112.5 µm (mean 138.8 by 101 µm). Clinically, patients presented with fever (39 - 40 °C) and abdominal pain. Some patients had pruritis around the mouth and their lips were swollen. 3 patients were treated and cured with single dose Triclabendazole. The remaining 302 patients were treated with Nitazoxanide and 122 (40 %) were cleared of infection with a single course. Snails of the genus Lymnaea were found in the surroundings. CONCLUSIONS: This report serves to remind medical professionals in East Africa that HF is a probable differential diagnosis in patients presenting with similar symptoms. It is possible to diagnose fascioliasis by light microscopy although specific antigen tests are required for confirmation. Human fascioliasis however, has not been described or reported in Tanzania before and begs further investigation.

Fascioliasis: An Ongoing Zoonotic Trematode Infection.

Zoonotic trematode infections are an area of the neglected tropical diseases that have become of major interest to global and public health due to their associated morbidity. Human fascioliasis is a trematode zoonosis of interest in public health. It affects approximately 50 million people worldwide and over 180 million are at risk of infection in both developed and underdeveloped countries. The one health paradigm is an area that seeks to address the problem of zoonotic infections through a comprehensive and sustainable approach. This review attempts to address the major challenges in managing human and animal fascioliasis with valuable insights gained from the one health paradigm to global health and multidisciplinary integration.

Could ehrlichial infection cause some of the changes associated with leukemia, myelodysplastic diseases and autoimmune disorders, and offer antibiotic treatment options?

We hypothesize that a large group of medical conditions of unknown etiology including leukemia, multiple myeloma, myelodysplastic and autoimmune disorders, may be associated with or caused by an obscure group of intracellular obligate parasitic bacteria named Ehrlichia/Anaplasma (EA). Ensconced in the stem cells of the bone marrow, EA may disrupt the normal development and function of many of the cells of immunity, manifesting itself as different syndromes. Recent studies of the activity of EA suggest direct effects on the immune system consistent with the manifestations of leukemia. We reference here three leukemia patients with direct or indirect evidence of EA infection. Moreover, EA have been shown to be most sensitive to rifamycins. Two moribund leukemia patients with levels of platelets and white cells incompatible with life were treated with therapeutic doses of Rifampin. Though they did not survive, their condition improved dramatically for a time, suggesting Rifampin provided some therapeutic benefit. We assert that these results warrant more extensive study.

Modernizing and transforming medical education at the Kilimanjaro Christian Medical University College.

The Kilimanjaro Christian Medical University (KCMU) College and the Medical Education Partnership Initiative (MEPI) are addressing the crisis in Tanzanian health care manpower by modernizing the college's medical education with new tools and techniques. With a $10 million MEPI grant and the participation of its partner, Duke University, KCMU is harnessing the power of information technology (IT) to upgrade tools for students and faculty. Initiatives in eLearning have included bringing fiber-optic connectivity to the campus, offering campus-wide wireless access, opening student and faculty computer laboratories, and providing computer tablets to all incoming medical students. Beyond IT, the college is also offering wet laboratory instruction for hands-on diagnostic skills, team-based learning, and clinical skills workshops. In addition, modern teaching tools and techniques address the challenges posed by increasing numbers of students. To provide incentives for instructors, a performance-based compensation plan and teaching awards have been established. Also for faculty, IT tools and training have been made available, and a medical education course management system is now being widely employed. Student and faculty responses have been favorable, and the rapid uptake of these interventions by students, faculty, and the college's administration suggests that the KCMU College MEPI approach has addressed unmet needs. This enabling environment has transformed the culture of learning and teaching at KCMU College, where a path to sustainability is now being pursued.

Introduction of team-based learning (TBL) at Kilimanjaro Christian Medical University College: experience with the ectoparasites module.

BACKGROUND: Contemporary teaching in sub-Saharan African medical schools is largely through didactic and problem-based approaches. These schools face challenges from burgeoning student numbers, severe faculty shortages, faculty without instruction in teaching methods and severe infrastructure inadequacies. Team-based learning (TBL) is a pedagogy which may be attractive because it spares faculty time. TBL was piloted in a module on ectoparasites at the Kilimanjaro Christian Medical University College (KCMU Co.). METHODS: TBL orientation began six weeks before starting the module. Students were issued background readings and individual and group readiness assessment tests, followed by module application, discussion and evaluation. At completion, student perceptions of TBL were assessed using a 5-point Likert scale evaluating six domains, with a score of 5 being most favourable. Strength of consensus measures (sCns) was applied. Final examination scores were compiled for 2011 (didactic) and 2012 (TBL). RESULTS: About 158 students participated in the module. The mean student scores across the six domains ranged from 4.2 to 4.5, with a high degree of consensus (range 85-90%). The final examination scores improved between 2011 and 2012. CONCLUSIONS: KCMU Co. student perceptions of TBL were very positive, and final exam grades improved. These observations suggest future promise for TBL applications at KCMU Co. and potentially other schools.

Improved glycemic control and acute complications among children with type 1 diabetes mellitus in Moshi, Tanzania.

OBJECTIVE: There are an estimated 1000 children with diabetes in Tanzania. Recently, the first two pediatric endocrinologists, trained in the European Society for Paediatric Endocrinology (ESPE)/International Society for Paediatric and Adolescent Diabetes (ISPAD) program in Nairobi, Kenya, entered practice. The purpose of this study was to prospectively assess the impact of a 6-month diabetes management and education program on glycemic control and acute complications in children and adolescents in Tanzania. RESEARCH DESIGN AND METHODS: Eighty-one patients aged 3-19 yr were enrolled. All were on split-dose Insulatard (Neutral Protamine Hagedorn) and Actrapid (soluble, regular) insulin, and were given three glucose test strips per week. Children were seen in clinic an average of six times over 6 months and received 3 h of diabetes education. A structured questionnaire evaluated social demographic data and acute complications. RESULTS: Despite regular clinic attendance, diabetes education, and provision of insulin, hemoglobin A1c (HbA1c) levels did not improve. Four children (5%) had HbA1c 7.5%, 22 (28%) HbA1c 7.5-10%, 9 (24%) HbA1c 11-12.5%, and 36 (44%) HbA1c >12.5%. There was a substantial reduction in severe hypoglycemia, with 17% of subjects experiencing this acute complication compared to 52% in the 6 months prior to study enrolment. Six children were admitted in diabetic ketoacidosis during the study compared to three during the previous 6 months. Twenty-six children (36%) reported missing >6 doses of insulin (but only two lacked insulin). CONCLUSIONS: Diabetes education significantly reduced the risk of severe hypoglycemia, but better glycemic control of diabetes was not attained. Further study is needed to explore factors to improve glycemic control including increased testing, or perhaps different insulin regimens.

Anopheline larval habitats seasonality and species distribution: a prerequisite for effective targeted larval habitats control programmes.

BACKGROUND: Larval control is of paramount importance in the reduction of malaria vector abundance and subsequent disease transmission reduction. Understanding larval habitat succession and its ecology in different land use managements and cropping systems can give an insight for effective larval source management practices. This study investigated larval habitat succession and ecological parameters which influence larval abundance in malaria epidemic prone areas of western Kenya. METHODS AND FINDINGS: A total of 51 aquatic habitats positive for anopheline larvae were surveyed and visited once a week for a period of 85 weeks in succession. Habitats were selected and identified. Mosquito larval species, physico-chemical parameters, habitat size, grass cover, crop cycle and distance to nearest house were recorded. Polymerase chain reaction revealed that An. gambiae s.l was the most dominant vector species comprised of An.gambiae s.s (77.60%) and An.arabiensis (18.34%), the remaining 4.06% had no amplification by polymerase chain reaction. Physico-chemical parameters and habitat size significantly influenced abundance of An. gambiae s.s (P = 0.024) and An. arabiensis (P = 0.002) larvae. Further, larval species abundance was influenced by crop cycle (P≤0.001), grass cover (P≤0.001), while distance to nearest houses significantly influenced the abundance of mosquito species larvae (r = 0.920;P≤0.001). The number of predator species influenced mosquito larval abundance in different habitat types. Crop weeding significantly influenced with the abundance of An.gambiae s.l (P≤0.001) when preceded with fertilizer application. Significantly higher anopheline larval abundance was recorded in habitats in pasture compared to farmland (P = 0.002). When habitat stability and habitat types were considered, hoof print were the most productive followed by disused goldmines. CONCLUSION: These findings suggest that implementation of effective larval control programme should be targeted with larval habitats succession information when larval habitats are fewer and manageable. Crop cycles and distance from habitats to household should be considered as effective information in planning larval control.

Effects of co-habitation between Anopheles gambiae s.s. and Culex quinquefasciatus aquatic stages on life history traits.

BACKGROUND: The effective measures for the control of malaria and filariasis vectors can be achieved by targeting immature stages of anopheline and culicine mosquitoes in productive habitat. To design this strategy, the mechanisms (like biotic interactions with conspecifc and heterospecific larvae) regulating mosquito aquatic stages survivorship, development time and the size of emerging adults should be understood. This study explored the effect of co-habitation between An. gambiae s.s. and Cx. quinquefasciatus on different life history traits of both species under different densities and constant food supply in the habitats of the same size under semi-natural conditions. METHODS: Experiments were set up with three combinations; Cx. quinquefasciatus alone (single species treatment), An. gambiae s.s. alone (single species treatment); and An. gambiae s.s. with Cx. quiquefasciatus (co-habitation treatment) in different densities in semi field situation. RESULTS: The effect of co-habitation of An. gambiae s.s. and Cx. quinquefasciatus was found to principally affect three parameters. The wing-lengths (a proxy measure of body size) of An. gambiae s.s. in co-habitation treatments were significantly shorter in both females and males than in An. gambiae s.s single species treatments. In Cx. quinquefasciatus, no significant differences in wing-length were observed between the single species and co-habitation treatments. Daily survival rates were not significantly different between co-habitation and single species treatments for both An. gambiae s.s. and Cx. quinquefasciatus. Developmental time was found to be significantly different with single species treatments developing better than co-habitation treatments. Sex ratio was found to be significantly different from the proportion of 0.5 among single and co-habitation treatments species at different densities. Single species treatments had more males than females emerging while in co-habitation treatments more females emerged than males. In this study, there was no significant competitive survival advantage in co-habitation. CONCLUSION: These results suggest that co-habitation of An. gambiae s.s. and Cx. quinquefasciatus in semi-natural conditions affect mostly An. gambiae s.s. body size. Hence, more has to be understood on the effects of co-habitation of An. gambiae s.s. and Cx. quinquefasciatus in a natural ecology and its possible consequences in malaria and filariasis epidemiology.

The role of cow urine in the oviposition site preference of culicine and Anopheles mosquitoes.

BACKGROUND: Chemical and behavioural ecology of mosquitoes plays an important role in the development of chemical cue based vector control. To date, studies available have focused on evaluating mosquito attractants and repellents of synthetic and human origins. This study, however, was aimed at seasonal evaluation of the efficiency of cow urine in producing oviposition cues to Anopheles gambiae s.l. and Culex quinquefasciatus in both laboratory and field conditions. METHODS: Oviposition response evaluation in laboratory conditions was carried out in mosquito rearing cages. The oviposition substrates were located in parallel or in diagonal positions inside the cage. Urine evaluation against gravid females of An. arabiensis and Cx. quinquefasciatus was carried out at Day 1, Day 3 and Day 7. Five millilitres (mls) of cow urine was added to oviposition substrate while de-chlorinated water was used as a control. In field experiments, 500 mls of cow urine was added in artificial habitats with 2500 mls of de-chlorinated water and 2 kgs of soil. The experiment was monitored for thirty consecutive days, eggs were collected daily from the habitats at 7.00 hrs. Data analysis was performed using parametric and non-parametric tests for treatments and controls while attraction of the oviposition substrate in each species was presented using Oviposition Activity Index (OAI). RESULTS: The OAI was positive with ageing of cattle urine in culicine species in both laboratory and field experiments. The OAI for anopheline species was positive with fresh urine. The OAI during the rainy season was positive for all species tested while in the dry season the OAI for culicine spp and Anopheles gambiae s.l., changed with time from positive to negative values.Based on linear model analysis, seasons and treatments had a significant effect on the number of eggs laid in habitats, even though the number of days had no effect. CONCLUSION: Oviposition substrates treated with cow urine in both laboratory and field conditions have shown that cow urine left to age from 1-7 days has an influence on oviposition behavioural response in mosquitoes. The analysis of microbial colonies for decaying urine should be investigated along with its associated by-products.

Durability associated efficacy of long-lasting insecticidal nets after five years of household use.

BACKGROUND: Long-lasting insecticidal nets (LLINs) have been strongly advocated for use to prevent malaria in sub-Saharan Africa and have significantly reduced human-vector contact. PermaNet® 2.0 is among the five LLINs brands which have been given full approval by the WHO Pesticide Evaluation Scheme (WHOPES). The LLINs are expected to protect the malaria endemic communities, but a number of factors within the community can affect their durability and efficacy. This study evaluated the durability, efficacy and retention of PermaNet® 2.0 after five years of use in a Tanzanian community. METHOD: Two to three day- old non blood-fed female mosquitoes from an insectary susceptible colony (An. gambiae s.s, this colony was established at TPRI from Kisumu, Kenya in 1992) and wild mosquito populations (An. arabiensis and Culex quinquefasciatus) were used in cone bioassay tests to assess the efficacy of mosquito nets. FINDINGS: The knockdown effect was recorded after three minutes of exposure, and mortality was recorded after 24 hours post-exposure. Mortality of An. gambiae s.s from insectary colony was 100% while An. arabiensis and Cx.quinquefasciatus wild populations had reduced mortality. Insecticide content of the new (the bed net of the same brand but never used before) and used PermaNet® 2.0 was determined using High Performance Liquid Chromatography (HPLC). CONCLUSION: The results of this study suggest that, in order to achieve maximum protection against malaria, public health education focusing on bed net use and maintenance should be incorporated into the mass distribution of nets in communities.

Predation efficiency of Anopheles gambiae larvae by aquatic predators in western Kenya highlands.

BACKGROUND: The current status of insecticide resistance in mosquitoes and the effects of insecticides on non-target insect species have raised the need for alternative control methods for malaria vectors. Predation has been suggested as one of the important regulation mechanisms for malaria vectors in long-lasting aquatic habitats, but the predation efficiency of the potential predators is largely unknown in the highlands of western Kenya. In the current study, we examined the predation efficiency of five predators on Anopheles gambiae s.s larvae in 24 hour and semi- field evaluations. METHODS: Predators were collected from natural habitats and starved for 12 hours prior to starting experiments. Preliminary experiments were conducted to ascertain the larval stage most predated by each predator species. When each larval instar was subjected to predation, third instar larvae were predated at the highest rate. Third instar larvae of An. gambiae were introduced into artificial habitats with and without refugia at various larval densities. The numbers of surviving larvae were counted after 24 hours in 24. In semi-field experiments, the larvae were counted daily until they were all either consumed or had developed to the pupal stage. Polymerase chain reaction was used to confirm the presence of An. gambiae DNA in predator guts. RESULTS: Experiments found that habitat type (P < 0.0001) and predator species (P < 0.0001) had a significant impact on the predation rate in the 24 hour evaluations. In semi-field experiments, predator species (P < 0.0001) and habitat type (P < 0.0001) were significant factors in both the daily survival and the overall developmental time of larvae. Pupation rates took significantly longer in habitats with refugia. An. gambiae DNA was found in at least three out of ten midguts for all predator species. Gambusia affins was the most efficient, being three times more efficient than tadpoles. CONCLUSION: These experiments provide insight into the efficiency of specific natural predators against mosquito larvae. These naturally occurring predators may be useful in biocontrol strategies for aquatic stage An. gambiae mosquitoes. Further investigations should be done in complex natural habitats for these predators.

Insecticidal activity of the essential oil from fruits and seeds of Schinus terebinthifolia Raddi against African malaria vectors.

BACKGROUND: Alternative insecticides for the control of malaria and filarial vectors are of paramount need as resistance is increasing among classes of insecticides currently in use in the public health sector. In this study, mosquitocidal activity of Schinus terebinthifolia essential oil against Anopheles gambiae s.s., An. arabiensis and Culex quinquefasciatus was assessed in laboratory, semi- field and full- field conditions METHOD: Twenty third instar larvae of both Anopheles gambiae s.s. and Cx. quinquefasciatus were exposed to different dosages of plant extract in both laboratory and semi- field environments. Observation of the mortality response was assessed at intervals of 12, 24, 48 and 72 hours. Adult semi- gravid female mosquitoes were exposed to papers treated with S. terebinthifolia and compared with WHO standard paper treated with alphacypermethrin (0.05%). RESULTS: Gas chromatography, coupled to mass spectrometry, identified 15 compounds from S. terebinthifolia extracts, the most abundant identified compound was δ-3-carene (55.36%) and the least was γ-elemene (0.41%). The density of the oil was found to be 0.8086 g/ml. The effective dosages in the insectary ranged from 202.15 to 2625.20 ppm and were further evaluated in the semi- field situation. In the laboratory, the mortality of Cx. quinquefasciatus ranged from 0.5 to 96.75% while for An. gambiae s.s it was from 13.75 to 97.91%. In the semi- field experiments, the mortality rates observed varied for both species with time and concentrations. The LC50 and LC95 value in the laboratory was similar for both species while in the semi- field they were different for each. In wild, adult mosquitoes, the KT50 for S. terebinthifolia was 11.29 minutes while for alphacypermethrin was 19.34 minutes. The 24 hour mortality was found to be 100.0% for S. terebinthifolia and 75.0% for alphacypermethrin which was statistically significant (P < 0.001). CONCLUSION: The efficacy shown by essential oils of fruits and seeds of S. terebinthifolia has given an opportunity for further investigation of individual components of these plant extracts and to evaluate them in small- scale field trials.

Saliva-based HIV testing among secondary school students in Tanzania using the OraQuick rapid HIV1/2 antibody assay.

HIV prevalence and knowledge concerning HIV prevention among secondary school students in Tanzania was investigated. Approximately 50% of all secondary school students in Hai district and Moshi town were included in the study. Saliva samples were obtained using the OraQuick rapid HIV-1/2 antibody assay. Forty-one (1.0%) and 211 (5.5%) students at the rural and urban schools, respectively, tested positive for HIV antibodies in saliva. HIV knowledge and beliefs varied significantly. Noninvasive saliva sample collection for HIV testing was highly acceptable. HIV infection is considerably more widespread among students attending urban rather than rural schools in the population investigated.