Human African Trypanosomiasis and challenges to its control in Urambo, Kasulu and Kibondo Districts, western Tanzania

A study was carried out to determine the prevalence and management of Human African Trypanosomiasis (HAT) in Urambo, Kasulu and Kibondo districts of western Tanzania. Parasitological surveys for trypanosome and other blood parasites were conducted in selected villages. Interviews with health workers were conducted to explore facility capacity to diagnose and manage HAT. Community knowledge on tsetse and availability of trypanocidal drugs was explored. Results showed that, although health facility records showed HAT is an important public health problem in the three districts, typanosomes were found in 0.6% of the examined individuals in Urambo district only. Malaria parasites with a prevalence of 12.1%, 19.7% and 9.7%, in Urambo, Kibondo and Kasulu, respectively were detected in blood samples from the same individuals examined for trypanosomes. There was poor capacity for most of the health facilities in the diagnosis, treatment and control of HAT. In both districts, communities were knowledgeable of the tsetse identity (82.4%) and had experienced tsetse bites (94%). The majority (91.4%) of the community members knew that they were at risk of acquiring HAT. However, only 29% of the respondents knew that anti-trypanocidal drugs were readily available free of charge from health care facilities. Late treatment seeking behaviour was common in Kasulu and Urambo districts. In conclusion, health facilities in western Tanzania are faced with problems of poor capacity to diagnose and manage HAT and that treatment seeking behaviour among the communities at risk is poor. Efforts should be made to strengthen the capacity of the health facility to handle HAT cases and health education to the population at risk. Keywords: Human African Trypanosomiasis, diagnosis, control, TanzaniaTanzania Health Research Bulletin Vol. 8 (2) 2006: pp. 80-8

Maternal Malaria Induces a Procoagulant and Antifibrinolytic State That Is Embryotoxic but Responsive to Anticoagulant Therapy

Low birth weight and fetal loss are commonly attributed to malaria in endemic areas, but the cellular and molecular mechanisms that underlie these poor birth outcomes are incompletely understood. Increasing evidence suggests that dysregulated hemostasis is important in malaria pathogenesis, but its role in placental malaria (PM), characterized by intervillous sequestration of Plasmodium falciparum, proinflammatory responses, and excessive fibrin deposition is not known. To address this question, markers of coagulation and fibrinolysis were assessed in placentae from malaria-exposed primigravid women. PM was associated with significantly elevated placental monocyte and proinflammatory marker levels, enhanced perivillous fibrin deposition, and increased markers of activated coagulation and suppressed fibrinolysis in placental plasma. Submicroscopic PM was not proinflammatory but tended to be procoagulant and antifibrinolytic. Birth weight trended downward in association with placental parasitemia and high fibrin score. To directly assess the importance of coagulation in malaria-induced compromise of pregnancy, Plasmodium chabaudi AS-infected pregnant C57BL/6 mice were treated with the anticoagulant, low molecular weight heparin. Treatment rescued pregnancy at midgestation, with substantially decreased rates of active abortion and reduced placental and embryonic hemorrhage and necrosis relative to untreated animals. Together, the results suggest that dysregulated hemostasis may represent a novel therapeutic target in malaria-compromised pregnancies

Blood cellular changes associated with bacteremia and malaria co-morbidity among children in western Kenya

Background: Malaria and bacteremia co-morbidity in children cause changes in blood cellular components. Complete blood count from children whose haemoglobin genotypes and bacteremia tests are not known, greatly influence clinical management and interpretation of the haematology results in resource limited healthcare facilities. Objectives: We investigated cellular components from children with bacteremia and malaria co-morbidity. We also analysed the haemoglobin genotypes and bacteria isolates from children with haemoglobin AA, SS and AS in western Kenya. Methods: A total number of 384 children were recruited and complete blood counts done with an automated cell counter. Microscopy was used to determine malaria infections, while bacteremia was determined by blood culture. The haemoglobin genotypes were analysed using the electrophoresis technique. Results: Children with haemoglobin AA and AS had elevated granulocyte counts. Most of the bacteria isolates were from children with malaria and haemoglobin AS. The bacteria isolated from blood culture included non-typhi salmonella, Escherichia coli, Enterobacter cloacae, Staphylococcus aureus, Listeria monocytogenes, Streptococcus pyogenes and Viridans. Salmonella species and staphylococcus aureus were the most prevalent bacteria isolates associated with bacteremia in children with haemoglobin AS and malaria positive. Conclusion: Children with Hb AS have higher chances of malaria and bacterial co-infection which leads to lymphocytopenia, erythrocytopenia and thrombocytopenia. Bacteria responsible for most of malaria co-infections in this region are Salmonella species and Staphylococcus aureus. The malaria and bacterial co-infection in pre-school children initiate differential cellular changes which should be investigated further

Seasonal epidemiological variation of human African trypanosomiasis in Babati District, Tanzania

No Abstract.Tanzania Health Research Bulletin Vol. 9(2) 2007: pp.136-13

The impact of different sprayable surfaces on the effectiveness of indoor residual spraying using a micro encapsulated formulation of lambda-cyhalothrin against Anopheles gambiae s.s

The type of sprayable surface impacts on residual efficacy of insecticide used in indoor residual spraying (IRS). However, there is limited data on common types of wall surfaces sprayed in Zanzibar and mainland Tanzania where IRS began in 2006 and 2007 respectively. The study investigated residual efficacy of micro-encapsulated lambda-cyhalothrin sprayed on common surfaces of human dwellings and domestic animal shelters in Zanzibar and mainland Tanzania.; An experimental hut was constructed with different types of materials simulating common sprayable surfaces in Zanzibar and mainland Tanzania. Surfaces included cement plastered wall, mud-daub, white-wash, wood, palm-thatch, galvanized iron-sheets, burnt-bricks, limestone and oil-paint. The World Health Organization (WHO) procedure for IRS was used to spray lambda-cyhalothrin on surfaces at the dose of 20-25 mg/m(2). Residual efficacy of insecticide was monitored through cone bioassay using laboratory-reared mosquitoes; Kisumu strain (R-70) of Anopheles gambiae ss. Cone bioassay was done every fortnight for a period of 152 days. The WHO Pesticide Evaluation Scheme (WHOPES) threshold (80% mortality) was used as cut-off point for acceptable residual efficacy.; A total of 5,800 mosquitoes were subjected to contact cone bioassay to test residual efficacy of lambda-cyhalothrin. There was a statistically significant variation in residual efficacy between the different types of wall surfaces (r = 0.24; p > 0.001). Residual efficacy decreased with increasing pH of the substrate (r = -0.5; p > 0.001). Based on WHOPES standards, shorter residual efficacy (42-56 days) was found in wall substrates made of cement, limestone, mud-daub, oil paint and white wash. Burnt bricks retained the residual efficacy up to 134 days while galvanized iron sheets, palm thatch and wood retained the recommended residual efficacy beyond 152 days.; The study revealed a wide variation in residual efficacy of micro encapsulated formulation of lambda-cyhalothrin across the different types of wall surfaces studied. In areas where malaria transmission is bimodal and wall surfaces with short residual efficacy comprise < 20% of sprayable structures, two rounds of IRS using lambda-cyhalothrin should be considered. Further studies are required to investigate the impact of sprayable surfaces on residual efficacy of other insecticides commonly used for IRS in Zanzibar and mainland Tanzania

Seasonal variation in human African trypanosomiasis in Tarangire National Park in Babati District, Tanzania

A survey was carried out to determine seasonal epidemiological variation of human African trypanosomiasis (HAT) in Tarangire National Park and villages around it in Babati District, Tanzania. Concentration and Field's stain techniques were employed to examine the presence of trypanosomes in human blood samples. Tsetse flies were collected using traps and dissected under light microscope to examine for presence of trypanosomes. Retrospective data on HAT were sought from health facilities. Blood samples were collected from a total 509 individuals (306 during the dry and 203 during wet seasons). None of the individuals was infected with trypanosomes in the area. A total of 766 tsetse flies were collected. Of these, Glossina swynnertoni   accounted for 94.6% and G. pallidipes for 5.4% of the total collection. The largest proportion (63.8%) of the tsetse flies was collected during the wet season. Glossina swynnertoni was most abundant tsetse species during both wet and dry seasons. Salivary gland examination revealed the presence of Trypanosoma brucei   type of infection in 3.2% of tsetse flies collected. All infective trypanosomes were found during the dry season. This study concludes that the transmission and prevalence of HAT among human population in Tarangire National Pars and its surrounding villages is low despite the recent reports on tourists acquiring the infection during their visits to the Park. However, disease surveillance needs to be strengthened to monitor any impending epidemic

Laboratory and field tests of Carbaryl 5% against fleas in Lushoto district, Tanzania

Background and Objective: Lushoto district has been an active focus of plague disease since 1980 and many pesticides were used to control rodents and fleas from 1980 to 2003 when outbreaks occurred yearly. For over seven years ago commercial Carbaryl 5% powder has been used for controlling fleas in the area. However, there is no current research to substantiate its effectiveness either in the laboratory or in the field. Methods: Immature stages of Xenopsylla brasiliensis were collected from two villages in Lushoto and transported to Sokoine University of Agriculture (SUA), Morogoro and reared in an insectary to stock colony. Known weights of commercial Carbaryl 5% powder were thoroughly mixed with known weights of clean fine sand as to obtain a final concentration of 0.05% (WW) of Carbaryl/sand mixture. The same concentration was suspended in 50cc distilled water and pieces of filter paper were soaked in the solution, left at room temperature until the suspension was fully adsorbed and the papers were left to dry. Adult fleas of mixed ages and of both sexes were obtained from the stock colony and exposed to both Carbaryl/sand mixture and Carbaryl-adsorbed filter papers for various periods of time. Field trials were carried out at Manolo and Viti villages where house and rodent flea indices were determined before and after dusting with commercial Carbaryl 5% powder. Results: In the laboratory tests, 100% mortality occurred at 90 minutes exposure in Carbaryl/sand mixture experiments and at 35 minutes exposure to Carbaryl-adsorbed filter papers. LT50 in both sets of exposure was 48.2 min and 23.1 min in Carbaryl/sand mixture and Carbaryl-coated filter papers tests respectively. In field trials, X. brasiliensis and Pulex irritans were the most abundant flea species. Post-dusting flea populations were significantly lower in treated than in control houses (p=0.028). House flea indices dropped from 7.7 to 0.33 and 37.8 to 0 in Viti and Manolo villages respectively at 3 months post-dusting. Conclusion: Commercial Carbaryl 5% powder in current use was still effective against potential flea vectors in Lushoto