Fever In Tanzania Research Articles

Farm and Livelihood Characteristics After ITM Vaccination Against East Coast Fever in Tanzania.

East Coast Fever is a critical cattle disease in East and Southern Africa which is currently mainly controlled through frequent chemical removal of ticks, the disease vector. However, a vaccine conveying life-long immunity has existed for some time, known as the infection and treatment method (ITM), although it has so far not been widely adopted because of its cost, demanding distribution system and regulatory reservations. Also, despite having proved effective on the animal level, the promoters of the vaccine have not been able to show much evidence of its benefits on the herd, farm and household levels. This study, based on a cross-sectional survey of 994 cattle keepers throughout Tanzania, aims to provide such evidence by comparing indicators of herd productivity, of farm management and success as well as of household livelihoods between households that have adopted the ITM vaccine for some years with those that have only recently adopted it. Econometric models identify the contribution of ITM adoption to indicator values together with various other determining factors amongst 277 long-term adopters of ITM and the control group of 118 recent adopters as well as 118 matched farmers without access to ITM. The results confirm that ITM adoption is positively associated with all three indicators of herd-productivity considered in this study. However, it does not support any of the three indicators of farm management and only one out of four indicators representing farm success. Nevertheless, the adoption of ITM shows a positive association with all four indicators of household livelihood. Investigating the chain of intermediate outcomes, indicators of herd productivity, such as milk yield, are significantly linked to higher feed expenses, contributing to increased livestock productivity and ultimately income and food availability. Overall, these results therefore support the promotion of ITM as a beneficial technology for the sustainable development of rural livestock keepers.

Molecular Detection and Typing of Pathogenic Leptospira in Febrile Patients and Phylogenetic Comparison with Leptospira Detected among Animals in Tanzania.

.Molecular data are required to improve our understanding of the epidemiology of leptospirosis in Africa and to identify sources of human infection. We applied molecular methods to identify the infecting Leptospira species and genotypes among patients hospitalized with fever in Tanzania and compared these with Leptospira genotypes detected among animals in Tanzania to infer potential sources of human infection. We performed lipL32 real-time PCR to detect the presence of pathogenic Leptospira in acute-phase plasma, serum, and urine samples obtained from study participants with serologically confirmed leptospirosis and participants who had died with febrile illness. Leptospira blood culture was also performed. In positive specimens, we performed species-specific PCR and compared participant Leptospira secY sequences with Leptospira reference sequences and sequences previously obtained from animals in Tanzania. We detected Leptospira DNA in four (3.6%) of 111 participant blood samples. We detected Leptospira borgpetersenii (one participant, 25.0%), Leptospira interrogans (one participant, 25.0%), and Leptospira kirschneri (one participant, 25.0%) (one [25%] undetermined). Phylogenetic comparison of secY sequence from the L. borgpetersenii and L. kirschneri genotypes detected from participants was closely related to but distinct from genotypes detected among local livestock species. Our results indicate that a diverse range of Leptospira species is causing human infection. Although our analysis suggests a close relationship between Leptospira genotypes found in people and livestock, continued efforts are needed to obtain more Leptospira genetic material from human leptospirosis cases to help prioritize Leptospira species and genotypes for control.

Monitoring vaccinated cattle for induction and longevity of persistent tick-transmissible infection: Implications for wider deployment of live vaccination against East Coast fever in Tanzania.

The infection and treatment (ITM) procedure remains the only available method of immunization against Theileria parva infection. One constraint to deployment is the perception that the carrier state induced by ITM could result in enhanced disease problems. More than one million cattle have been ITM vaccinated in pastoralist systems in Tanzania over the last 2 decades. We present the results of a longitudinal study of six groups of cattle in Maasai villages in northern Tanzania exposed to natural tick challenge for between 2weeks and 14years post-vaccination. The p104 nested PCR revealed a higher frequency of T.parva carriers among vaccinates (30%) compared with controls (8%) (OR=4.89, p=.000), with the highest frequency of carriers found in calves vaccinated 6months previously, although carrier state was also detected in cattle vaccinated >10years prior to the study. Variable number tandem repeat genotype analysis revealed 6 MS7 alleles with sizes ranging from 150bp to 500bp, but only two alleles were detected in cattle vaccinated >4years earlier, relative to five alleles detected in recently vaccinated cattle and controls. In terms of heterozygosity, diversity was maximal in calves vaccinated within the last 2weeks (h=0.776) but lowest in cattle vaccinated 4years earlier (h=0.375). The analysis suggested close genetic relatedness of parasites in vaccinated and unvaccinated groups and up to 96% of variation was within rather than between the groups. These results confirm that ITM leads to a long-term T.parva carrier state in cattle and the detection of vaccine component VNTR in co-grazing unvaccinated cattle suggests potential vaccine transmission by ticks. However, vaccination stocks did not totally replace local genotypes, at least in cattle populations. These findings should mitigate concerns that ITM modifies T.parva field populations in a way that enhances disease in the medium term.

Evidence of Chikungunya but not Dengue Virus Circulating among Febrile Patients during Low Transmission Period in Morogoro Municipality, Tanzania

Background: There is currently sufficient evidence available indicating that dengue and chikungunya viruses could be among the causes of fever in Tanzania. Overlapping clinical manifestations of chikungunya and dengue with other vector-borne parasitic diseases pose a challenge for medical diagnosis in Tanzania. A virus surveillance study was conducted in Morogoro Municipality which had no reports of outbreaks during high risk of transmission with dengue epidemics in the neighbouring Dar es Salaam.
 Methodology: The present study was carried out to screen for dengue (DENV) and chikungunya (CHIKV) in sera from patients with fever and malaria-like symptoms on selected health centres in Morogoro municipality (n = 5) during March-May 2018. Three hundred and twelve febrile individuals presenting to the outpatient department were screened for the presence of chikungunya and dengue viruses using Multiplex real-time reverse transcription-polymerase chain reaction.
 Results: Acute CHIKV infection was confirmed in four (1.28%) cases whereas no acute DENV infection was detected. Acute chikungunya cases were exclusively prevailing amongst female patients aged between 20 and 49 years.
 Conclusion: Our findings indicate an active circulation of chikungunya virus among febrile patients seeking medical attention in Morogoro Municipality, Tanzania. The improvement of CHIKV case detection and reporting is critical to its control and prevention. Surveillance programmes in monitoring arboviral activities in human populations as well as in mosquitos should be performed to avoid maintenance of CHIKV in mosquitoes that may lead to future outbreaks.

Symptomatic and asymptomatic cases of African swine fever in Tanzania.

African swine fever (ASF) is an acute, highly contagious and deadly viral haemorrhagic disease of domestic pigs caused by African swine fever virus (ASFV). In ASF endemic countries, there are an increasing number of reports on circulating ASFV strains with different levels of virulence causing a broad range of clinical symptoms in susceptible animals. Tanzania, where ASFV is endemic since 2001, recorded several outbreaks including symptomatic and asymptomatic cases between 2015 and 2017. We collected 35 clinical samples from four outbreaks for diagnostic confirmation and sequenced the partial B646L (p72), the full E183L (p54) gene, the central variable region of the B602L gene and the intergenic region between the I73R and I329L genes to characterize molecularly the new ASFV isolates and analyse their relatedness with previously reported Tanzanian and foreign isolates. We detected ASFV in 21 samples, 15 from symptomatic and six from asymptomatic pigs. Phylogenetic analyses based on the partial p72 gene and the complete p54 (E183L) genes revealed that the ASFVs in samples from symptomatic pigs belonged to genotypes II and those in samples from asymptomatic pigs belonged to genotype IX. The CVR profiles of the p72 genotype II and genotype IX isolates differed between each other and from previously published Tanzanian sequences. The sequence analysis of the intergenic region between the I73R and I329L for the 2017 genotype II isolates showed the absence of one GGAATATATA motif in those isolates. This study showed the simultaneous circulation of two different ASFV genotypes with different levels of pathogenicity in Tanzania. Since the existence of sub-clinically infected pigs may contribute to the persistence of the virus, our findings suggest continuous surveillance and characterization of ASFV isolates in disease-endemic regions.

Zoonotic Rift Valley fever virus prevalence and risk factors in the Lake Zone of Tanzania

Zoonotic Rift Valley fever virus prevalence and risk factors in the Lake Zone of Tanzania

A review on prevalence, control measure, and tolerance of Tanzania Shorthorn Zebu cattle to East Coast fever in Tanzania.

In Tanzania, control of East Coast fever (ECF) has predominantly relied on tick control using acaricides and chemotherapy, little on ECF vaccination, and very little on dissemination regarding animal immunization. In this paper, the prevalence, control measure, and tolerance of Tanzania Shorthorn Zebu (TSHZ) cattle to ECF are reviewed. In addition, the opportunities available for reducing the use of acaricides for the benefit of the farmers in terms of reduction of costs of purchasing acaricides and environmental pollution are described. The tick distribution and epidemiological factors for ECF such as the agro-ecological zones (AEZ), livestock production systems (LPS), strain, and age of the animals are also described. These factors influence the epidemiology of ECF and the distribution of TSHZ strains in different geographic locations of Tanzania. We have further showed that there is a tendency of farmers to select among the strains of TSHZ for animals which can tolerate ticks and ECF and crossbreed them with their local strains with the aim of benefiting from the inherent characteristics of the most tolerant strains. Generally, many strains of TSHZ cattle are tolerant to tick infestation and ECF infection and can be bred to respond to the needs of the people. In this review paper, we recommend that in future, ECF epidemiological studies should account for factors such as livestock production system, agro-climate, breed of animal, tick control strategy, and the dynamic interactions between them. In conclusion, we have demonstrated that an integrated control method involving use of acaricides, immunization, and ECF-tolerant/-resistant animals is required.

Factors Associated with Testing and Prompt Use of Recommended Antimalarials following Malaria Diagnosis: A Secondary Analysis of 2011-12 Tanzania HIV and Malaria Indicator Survey Data.

IntroductionMalaria is still a public health problem in Sub-Saharan Africa. Malaria causes mortality mostly in children under-five years. Early detection and prompt treatment using recommended antimalarials is key to malaria control. However, in Tanzania, contrary to the national goals, a large proportion of children with fever taken to health facilities are not tested for malaria and those tested positive are not promptly treated using recommended antimalarials. The aim of this study was to determine factors associated with malaria testing and prompt use of recommended antimalarials among under-five children with fever in Tanzania.MethodsThis was a secondary analysis of Tanzania HIV and Malaria Indicator Survey (THMIS) data 2011-12 obtained from a national cross sectional survey. The analysis involved children aged 6-59 months whose mothers reported they had fever two weeks preceding the survey. Factors associated with testing and uses of recommended antimalarials were obtained using logistic regression.ResultsOf the 1675 under-five children with fever, 951 (56.8%) were taken to the health facilities. Of the 951 children, only 394 (41.48%) febrile children were tested for malaria. Of those tested, 291 (78.91%) were diagnosed with malaria. Of those diagnosed with malaria, only 124 (42.68%) children used recommended antimalarials within 1st 24 hours of diagnosis. In multivariate analysis, children taken to health centers (OR 1.79; 95%CI: 1.07 - 3.00) and to the hospitals (OR 3.4; 95%CI: 1.75 - 6.77) had higher odds of being tested compared to those taken to dispensary and other lower level health facilities. Children were more likely to use recommended antimalarial promptly if they had a caretaker with secondary or higher education (OR: 4.07; 95%CI: 0.61 - 2.68) or living in the rural area (OR: 3.21; 95%CI: 1.09 - 9.44) compared to those with an uneducated caretaker or from an urban area.ConclusionTraining on malaria testing and treatment guidelines should be provided, and preventing stock outs of malaria testing kits and medications at dispensary level should be made available as it is the first point of health care for most Tanzanians. Reasons on why urban people are less likely to use recommended antimalarials need to be investigated and addressed for proper malaria management.

Identification of the Immunogenic Outer Membrane Proteins of Relapsing Fever <i>Borrelia</i>

Borrelia duttonii, a causative agent of relapsing fever, is transmitted between the distinct microenvironments of the vector tick, Ornithodoros moubata, and a mammalian host. We identified the total and membrane fraction proteins of B. duttonii strain Ly isolated from a patient in Tanzania by using two-dimensional gel electrophoresis with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The analyses of the total and membrane fractions from bacterial cultures incubated at 37°C identified 68 and 15 proteins, respectively. Since spirochaete clearance in mice is associated with an immunoglobulin M (IgM) and immunoglobulin G3 (IgG3)-mediated response, immunoblot analyses were used to identify the proteins reactive with IgM and IgG3 of gerbil serum against B. duttonii strain Ly. The outcome showed that six proteins (antigen p83/100, membrane-associated protein P66 (P66), flagellar filament outer layer protein, hypothetical protein BDU_412, vlp protein gamma subfamily (γ-Vlp) and flagellin (FlaB)) were identified against IgM, and four (antigen p83/100, P66, γ-Vlp and FlaB) of the six proteins also reacted with IgG3. It is believed that these proteins are immunodominant antigens for the host immune response. Some of these immunogenic proteins might be used as molecular diagnostic tools in the study of relapsing fever in Tanzania.

Response to Rift Valley Fever in Tanzania: Challenges and Opportunities.

Rift Valley Fever (RVF) is an arthropod borne viral disease affecting livestock (cattle, sheep, goats and camels), wildlife and humans caused by Phlebovirus. The disease occurs in periodic cycles of 4-15 years associated with flooding from unusually high precipitations in many flood-prone habitats. Aedes and Culex spp and other mosquito species are important epidemic vectors. Because of poor living conditions and lack of knowledge on the pathogenesis of RVF, nomadic pastoralists and agro-pastoralists are at high risk of contracting the disease during epidemics. RVF is a professional hazard for health and livestock workers because of poor biosafety measures in routine activities including lack of proper Personal Protective Equipment (PPE). Direct exposure to infected animals can occur during handling and slaughter or through veterinary and obstetric procedures or handling of specimens in laboratory. The episodic nature of the disease creates special challenges for its mitigation and control and many of the epidemics happen when the governments are not prepared and have limited resource to contain the disease at source. Since its first description in 1930s Tanzania has recorded six epidemics, three of which were after independence in 1961. However, the 2007 epidemic was the most notable and wide spread with fatal human cases among pastoralists and agro-pastoralists concurrent with high livestock mortality. Given all the knowledge that exist on the epidemiology of the disease, still the 2006/2007 epidemic occurred when the government of Tanzania was not prepared to contain the disease at source. This paper reviews the epidemiology, reporting and outbreak-investigation, public awareness, preparedness plans and policy as well as challenges for its control in Tanzania.

The bacteraemia of disseminated tuberculosis among HIV-infected patients with prolonged fever in Tanzania

Disseminated tuberculosis (TB) is a common cause of death among human immunodeficiency virus (HIV)-infected patients in developing countries. Blood culture offers a potential means to diagnose disseminated TB, but optimal blood culture methods have not been studied. Two hundred and fifty-eight HIV-infected patients hospitalized in Tanzania with ≥2 weeks fever or cough had diagnostic studies for TB: 3 sputum samples for acid-fast bacilli smear and culture; 40 ml of blood for culture, randomized 1:1 to 40 ml × 1, or 20 ml × 2 collected 12-24 h apart. Blood was processed using automated MB BacT(®) broth and manual Isolator(®) lysis-centrifugation agar. Mortality was assessed at 2 months. TB was confirmed in 83 (32%) of 258 patients: by sputum only in 42 (51%, median CD4 = 72 cells/μl), blood only in 15 (18%, median CD4 = 44 cells/μl), and in sputum and blood in 26 (31%, median CD4 = 12 cells/μl). Blood was positive in 21 (16%) for 40 ml × 1 vs 20 (15%) for 20 ml × 1 (p = 0.83) vs 20 (16%) for 20 ml × 2 (p = 0.97). MB BacT was positive in 31 (76%) and Isolator was positive in 20 (49%) of 41 samples (p = 0.01). The mean colony-forming units/ml was 8 (range 3-14). Twenty-one (51%) patients with disseminated TB died; median survival was 6 days (range 0-58). Disseminated TB in HIV is characterized by persistent bacteraemia, delayed microbiological detection, and high mortality. Twenty millilitres of blood processed by automated broth is the optimal culture method to detect disseminated TB. Empiric TB therapy is warranted for HIV-infected patients from TB-endemic countries with prolonged cough or fever.

Immunodominant Epitope in the C‐Terminus of a Variable Major Protein in Borrelia duttonii, an Agent of Tick‐Borne Relapsing Fever

Borrelia duttonii strain Ly was isolated from a child with tick-borne relapsing fever in Tanzania. B. duttonii produces variable major proteins (Vmps), which undergo antigenic variation. We previously reported transcription of the vmpP gene, which is one of the Vmp genes in strain Ly, detected in vitro cultivation. In the current study, we purified the recombinant non-lipidated VmpP protein by affinity chromatography and produced VmpP polyclonal antibodies. Antigenicity of VmpP was examined by Western immunoblot analysis and peptide-based enzyme-linked immunosorbent assays. Antigenic epitopes were shown to comprise five regions interspersed within the VmpP primary amino acid sequence. Synthetic peptides spanning residues of three of five regions, 232-237 (LASIVD), 280-285 (AGGIAL), and 350-355 (KAADQQ), reacted strongly with the VmpP-specific antibody and these residues were identified as epitopes. In particular, the C-terminal domain (KAADQQ) of this protein was immunoreactive. Further research based on our results will promote the development of a recombinant vaccine for B. duttonii infection.

Evaluation of buparvaquone (BUTA-Kel™ KELA, Belgium) as a treatment of East Coast fever in cattle, in the peri-urban of Dar Es Salaam city, Tanzania

Evaluation trials of the efficacy of buparvaquone (BUTA-kel™ KELA Laboratoria, N.V. Belgium), as a treatment of field cases of Theileria parva infection (East Coast fever – ECF) were carried out on 63 cattle in the peri-urban of Dar Es Salaam city, Tanzania, during the period November 2004 to August 2005. Thirty-two cattle (56%) received single-dose treatment (2.5 mg buparvaquone per kg body weight), while two and three-dose treatment with interval(s) of 48 h was given to 33% and 11% of total treated cattle, respectively; 38 cattle (60.3%) were treated at an early stage of the disease, while 25 cattle (39.7%) were treated at an advanced stage of the disease. The rectal body temperature of 90.5% of buparvaquone-treated cattle dropped to normal values (37.5–39.5 °C) by day 7 of treatment, and by day 15 of treatment 96.8% of treated cattle showed normal values. Pulmonary signs were observed in 8/68 (11.8%) of total ECF diagnosed cattle and were successfully treated, albeit with parvaquone plus frusemide (Fruvexon); were not included in final evaluation of the efficacy of BUTA-kel. The present evaluation trials record a recovery rate of 95.2%. Buparvaquone (BUTA-kel™ KELA Laboratoria, N.V. Belgium), therefore, records another efficacious and valuable alternative treatment against East Coast fever in Tanzania.

Absence of focal neurological involvement in tick‐borne relapsing fever in northern Tanzania

The aim of the study was to chart incidence and clinical features of tick-borne relapsing fever in Tanzania. Consecutive patients with fever and spirochetes demonstrated in a thick blood smear at Haydom Lutheran Hospital from 1 January to 31 December 2003 underwent clinical and cerebrospinal fluid (CSF) examination. Forty-four patients were included, making an estimated minimum annual incidence of 11 per 100 000 population in this region. The mortality rate was 2.3% (95% CI = 0-12). The most frequent complaints were generalized malaise (93%), headache (86%), nausea and vomiting (52%). None of the patients [0% (95% CI = 0-8)] had focal neurological symptoms. Cell count in CSF was normal in 22 and slightly elevated (6-12 leukocytes/mm(3)) in 20 patients. Two of three pregnancies had a poor outcome. Jarisch-Herxheimer reactions, bleeding complications and ocular manifestations were infrequent. In conclusion, tick-borne relapsing fever is a common disease in the Northern highland of Tanzania, but in contrast to other parts of the world, neurological involvement is uncommon in this area.

A newly identified tick-borne Borrelia species and relapsing fever in Tanzania

Tick-borne relapsing fever caused by the spirochaete Borrelia duttonii is a common cause of serious illness in central Tanzania. Screening of Ornithodoros sp ticks from infested houses for the presence of B duttonii had detected a previously unidentified species of Borrelia. We investigated whether this species infected the human population in a central Tanzanian village, by use of blood slide examination and PCR. PCR was twice as sensitive in detection of infections, showing Borrelia sp in six (11%) of 54 children with fever, and in 13 (4%) of 307 otherwise healthy children. Genotyping Borrelia from 17 infections identified Borrelia duttonii and an unnamed species. Our findings show that the newly discovered species is a causal agent of tick-borne relapsing fever.

Severe anaemia due to haematopoietic precursor cell destruction in field cases of East Coast Fever in Tanzania

Examinations were made on erythrocytes, thrombocytes, leukocytes, lymph nodes, thymus, haemal nodes and bone marrow in field cases of East Coast Fever (ECF) in Tanzania. Seventy-six clinically sick short-horn Zebu and Taurine-Zebu crosses, positive for Theileria parva piroplasms and schizonts and 55 apparently healthy cattle were studied. The syndrome observed was characterized by severe pancytopenia, with massive normocytic, normochromic anaemia, panleukopenia and thrombocytopenia, but no reticulocytes in peripheral blood. The erythrocyte and leukocyte counts, haematocrit and haemoglobin concentrations were greatly decreased compared with those of the healthy cattle. The means ±SD (with values of healthy cattle in parentheses) were 2.85 ± 1.10 (6.04 ± 1.58) × 10 121 −1, 2.78 ± 1.70 (10.59 ± 4.16) × 10 9 1 −1, 0.19 ± 0.06 (0.31 ± 0.054)1 1 −1 and 4.07 ± 1.62 (7.29 ± 1.39) mmol 1 −1 respectively. Lymphoproliferation was low, while lymphocyte destruction (lymphocytolysis) was high. There were very few small schizonts in parotid and prescapular glands. Lymphocytes were extensively destroyed in medullary cords, germinal centres of lymph nodules in cortex and paracortical regions of lymph nodes and haemal nodes. The bone marrow was hypocellular, with only a few haematopoietic precursor erythroid, granulocytic and thrombopoietic cell series. All stages of prorubriblasts and rubricytes had granulated nuclei, some with schizonts. Infection of erythrocytes by merozoites appeared to take place in precursor stages. The destruction of erythroblasts, rubricytes and other haematopoietic cells resulted in anaemia without reticulocytosis, haemoglobinuria and jaundice, accompanied by panleukopenia of extreme neutropenia, lymphopenia and eosinopenia. This indicated that this T. parva strain differs from previously described buffalo- or cattle-derived T. parva infections in causing both haemoproliferation and lymphoproliferation by extensive haematopoitic cell destruction and lymphocytolysis. In cattle- and buffalo-derived T. parva infections, anaemia is normally mild and there are numerous large schizonts in the former.