Browsing by Author "Kazwala, R. R."

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A ‘‘One Health’’ approach to address emerging zoonoses: The HALI project in Tanzania
(PLoS Medicine) Mazet, J. A. K.; Clifford, D. L.; Coppolillo, B. P.; Deolalikar, A. B.; Erickson, J. D.; Kazwala, R. R.
A ‘‘One Health’’ approach to address emerging zoonoses: The HALI project in Tanzania
(PLoS Medicine, 2009-12) Mazet, J. A. K.; Clifford, D. L.; Coppolillo, B. P.; Deolalikar, A. B.; Erickson, J. D.; Kazwala, R. R.
Every day thousands of children and adults die from underdiagnosed diseases that have arisen at the human–animal– environment interface, especially diarrheal and respiratory diseases in developing countries [1,2]. Explosive human population growth and environmental changes have resulted in increased numbers of people living in close contact with wild and domestic animals. Unfortunately, this increased contact together with changes in land use, including livestock grazing and crop production, have altered the inherent ecological balance between pathogens and their human and animal hosts. In fact, zoonotic pathogens, such as influenza and SARS (severe acute respiratory syndrome), account for the majority of emerging infectious diseases in people [3], and more than three-quarters of emerging zoonoses are the result of wildlife-origin pathogens [4]. While zoonoses represent a significant emerging threat to public health, many of these diseases, such as diarrheal diseases arising from poor water sanitation, are neglected by funding agencies [5].
A cross-sectional study of factors associated with dog ownership in Tanzania
Knobel, D. L.; Laurenson, M. K.; Kazwala, R. R.; Boden, L. A.; Cleaveland, C.; Mfinanga, S. G. M.
A cross-sectional study of factors associated with dog ownership in Tanzania
(2008-01-29) Knobel, D. L.; Laurenson, M. K.; Kazwala, R. R.; Boden, L. A.; Cleaveland, C.; Mfinanga, S. G. M.
Background: Mass vaccination of owned domestic dogs is crucial for the control of rabies in sub- Saharan Africa. Knowledge of the proportion of households which own dogs, and of the factors associated with dog ownership, is important for the planning and implementation of rabies awareness and dog vaccination programmes, and for the promotion of responsible dog ownership. This paper reports the results of a cross-sectional study of dog ownership by households in urban and rural communities in the United Republic of Tanzania. Results: Fourteen percent (202) of 1,471 households surveyed were identified as dog-owning, with an average of 2.4 dogs per dog-owning household. The percentage of dog-owning households was highest in inland rural areas (24%) and lowest in coastal urban communities (7%). The overall human:dog ratio was 14:1. Multivariable logistic regression revealed that households which owned cattle, sheep or goats were much more likely to own dogs than households with no livestock. Muslim households were less likely to own dogs than Christian households, although this effect of religion was not seen among livestock-owning households. Households were more likely to own a dog if the head of the household was male; if they owned a cat; or if they owned poultry. Dog ownership was also broadly associated with larger, wealthier households. Conclusion: The human:dog ratios in Tanzania are similar to those reported elsewhere in sub- Saharan Africa, although cultural and geographic variation is evident. Estimation of the number of owned dogs, and identification of household predictors of dog ownership, will enable targeted planning of rabies control efforts.
A field vaccine trial in Tanzania demonstrates partial protection against malignant catarrhal fever in cattle
(ELSEVIER) Lankester, F.; Russell, G. C.; Lugelo, A.; Ndabigaye, A.; Mnyambwa, N.; Keyyu, J.; Kazwala, R. R.; Grant, D; Percival, A.; Deane, D.; Haig, D. M.; Cleaveland, S.
A field vaccine trial in Tanzania demonstrates partial protection against malignant catarrhal fever in cattle
(ELSEVIER, 2015) Lankester, F.; Russell, G. C.; Lugelo, A.; Ndabigaye, A.; Mnyambwa, N.; Keyyu, J.; Kazwala, R. R.; Grant, D; Percival, A.; Deane, D.; Haig, D. M.; Cleaveland, S.
Malignant catarrhal fever (MCF) is a fatal lymphoproliferative disease of cattle that, in East Africa, results from transmission of the causative virus, alcelaphine herpesvirus 1 (AlHV-1), from wildebeest. A vaccine field trial involving an attenuated AlHV-1 virus vaccine was performed over two wildebeest calving seasons on the Simanjiro Plain of northern Tanzania. Each of the two phases of the field trial consisted of groups of 50 vaccinated and unvaccinated cattle, which were subsequently exposed to AlHV-1 challenge by herding toward wildebeest. Vaccination resulted in the induction of virus-specific and virus-neutralizing antibodies. Some cattle in the unvaccinated groups also developed virus-specific antibody responses but only after the start of the challenge phase of the trial. PCR of DNA from blood samples detected AlHV-1 infection in both groups of cattle but the frequency of infection was significantly lower in the vaccinated groups. Some infected animals showed clinical signs suggestive of MCF but few animals went on to develop fatal MCF, with similar numbers in vaccinated and unvaccinated groups. This study demonstrated a baseline level of MCF-seropositivity among cattle in northern Tanzania of 1% and showed that AlHV-1 virus-neutralizing antibodies could be induced in Tanzanian zebu shorthorn cross cattle by our attenuated vaccine, a correlate of protection in previous experimental trials. The vaccine reduced infection rates by 56% in cattle exposed to wildebeest but protection from fatal MCF could not be determined due to the low number of fatal cases.
A globally important clonal complex of Mycobacterium bovis
(Elsevier) Smith, N. H.; Berg, S.; Dale, J.; Allen, A.; Rodriguez, S.; Romero, B.; Kazwala, R. R.; Hilty, M.
Antimicrobial resistance and genotypic diversity of Campylobacter isolated from pigs, dairy, and beef cattle in Tanzania
(Frontiers in Microbiology) Kashoma, I. P.; Kassem, I. I.; Kumar, A.; Kessy, B. M.; Gebreyes, W.; Kazwala, R. R.; Rajashekara, G.
Association of long-term pesticide exposure and biologic parameters in female farm workers in Tanzania: A cross sectional study
(Toxics) Manyilizu, W. B.; Mdegela, R. H.; Kazwala, R. R.; Nonga, H. E.; Müller, M. B.; Lie, E.; Skjerve, E.; Lyche, J. L.
Association of long-term pesticide exposure and biologic parameters in female farm workers in Tanzania: A cross sectional study
(Toxics, 2016-09-29) Manyilizu, W. B.; Mdegela, R. H.; Kazwala, R. R.; Nonga, H. E.; Müller, M. B.; Lie, E.; Skjerve, E.; Lyche, J. L.
The study aimed to assess the association of long-term pesticide exposure (5 years) with hematological, serum biochemical parameters and acetylcholinesterase activity in farm workers. These pesticides included organophosphorus pesticides, carbamates, pyrethroids, dithiocarbamates, and other pesticides such as endosulfan. Applying a cross-sectional study design, 69 females from a pesticide-exposed farm population and 30 females from a district not using pesticides (reference group) were studied. The mean red cell corpuscular volume and hematocrit values were significantly lower (74.7 9.1 fl; 95% CI 72.5–76.9 and 32.0% 4.6%; 95% CI 30.9–33.1, respectively) in the exposed compared to the reference group, whereas mean corpuscular hemoglobin concentration and platelets were significantly higher (37.4 3.8 g/dL; 95% CI 36.5–38.3 and 374.1 95.3/L; 95% CI 351.2–396.9, respectively) in the exposed compared to the reference group. Mean serum glutamic oxaloacetate transaminase (20.7 8.9 U/L; 95% CI 18.5–22.9) and creatinine (83.9 6.6 mol/L; 95% CI 82.3–85.5) were significantly higher in the exposed compared to the reference group. A higher mean esterase activity (AChE 0.6 0.2 mM/min/mg protein; 95% CI 0.56–0.7; BChE 0.9 0.4 mM/min/mg protein; 95% CI 0.9–1.1) was noted in the exposed group. Regression models suggest that occupational exposure (p < 0.001) could be a predictor of esterase (AChE and BChE) activity and biochemical changes (= 0.4, 95% CI: 0.3–0.5; = 0.7, 95% CI: 0.6–0.9, respectively). Long-term pesticide exposure affects the hemato-biochemical and esterase responses, establishing the need for further studies.
Boma to banda - A disease sentinel concept for reduction of diarrhoea
(Pastoralism: Research, Policy and Practice.) Wolking, D. J.; Clifford, D. L.; Kelly, T. R.; Kamani, E.; Smith, W. A.; Kazwala, R. R.; Mazet, J. A.K.
Boma to banda - A disease sentinel concept for reduction of diarrhoea
(Pastoralism: Research, Policy and Practice., 2016) Wolking, D. J.; Clifford, D. L.; Kelly, T. R.; Kamani, E.; Smith, W. A.; Kazwala, R. R.; Mazet, J. A.K.
Diarrhoeal diseases can be debilitating, especially for children and young animals. In many rural areas, particularly pastoral communities, livelihoods are characterized by close interaction between household members and their livestock herds, and children often care for young animals, creating opportunities for the transmission of multiple zoonotic pathogens. Using a One Health approach, we first evaluated whether diarrhoeal diseases were a problem for pastoral households in Tanzania and then investigated their calf herds to identify the prevalence and risk factors for diarrhoeal disease and the shedding of the zoonotic pathogens Cryptosporidium and Giardia. Sixty percent of households reporting cases of human diarrhoea also had diarrhoea detected later in their calf herds, and calf herds shedding Cryptosporidium oocysts were six times more likely to be diarrhoeic. Because Cryptosporidium shares a similar transmission mode with a wide range of diarrhoeagenic organisms and calf diarrhoea outbreaks can involve multiple pathogens with mixed infections, it is possible that calf diarrhoea may be indicative of shared risk of zoonotic pathogens from environmental contamination. To mitigate the risk of transmission of faecal-borne zoonotic pathogens from herds to households (boma-livestock pens to banda –household building), we describe a conceptual disease early-warning method proposing diarrhoeic calves as animal sentinels. Such a calf warning system, combined with appropriate interventions designed to minimize exposure, could serve as a practical solution for reducing risks of diarrhoeal diseases among animals and people.
Epidemiology and RAPD-PCR typing of thermophilic campylobacters from children under five years and chickens in Morogoro municipality, Tanzania
(BMC) Chuma, I. S.; Nonga, H. E.; Mdegela, R. H.; Kazwala, R. R.
Epidemiology and RAPD-PCR typing of thermophilic campylobacters from children under five years and chickens in Morogoro Municipality, Tanzania
(BMC Infectious DiseasesBMC serie) Chuma, I. S.; Nonga, H. E.; Mdegela, R. H.; Kazwala, R. R.
Epidemiology and RAPD-PCR typing of thermophilic campylobacters from children under five years and chickens in Morogoro municipality, Tanzania
(BMC, 2016-06-15) Chuma, I. S.; Nonga, H. E.; Mdegela, R. H.; Kazwala, R. R.
Background: Campylobacter species are gram negative and flagellated bacteria under the genus Campylobacter, family Campylobacteriaceae. These pathogens cause zoonotic infections among human and animal populations. This study was undertaken between December 2006 and May 2007 to determine prevalence, risk factors and genetic diversity of thermophilic Campylobacter isolates from children less than 5 years and chickens in Morogoro Municipality, Tanzania. Methods: The Skirrow’s protocol was used for isolation and identification of Campylobacter from 268 human stool specimens and 419 chicken cloacal swabs. Patient biodata and risk factors associated with human infection were also collected. Genetic diversity of Campylobacter isolates was determined by a RAPD-PCR technique using OPA 11 primer (5′-CAA TCG CCG T-3′). Phylogenetic analysis and band pattern comparison were done by Bionumerics software and visual inspection. Results: Stool samples from 268 children and 419 cloacal swabs from chickens were analyzed. Prevalence of thermophilic Campylobacters in children was 19% with higher isolation frequency (p = 0.046) in males (23.5%) than females (13.8%). Campylobacter jejuni (78.4%) was more isolated (p = 0.000) than C. coli (19.6%) and 2% were unidentified isolates. In chickens, the prevalence was 42.5% with higher isolation rate (p = 0.000) of C. jejuni (87%) than C. coli (13%). Campylobacters were more frequently recovered (p = 0.000) from indigenous/ local chickens (75.0%) followed by cockerels (52.2%), broilers (50.0%) and lowest in layers (22.7%). Keeping chickens without other domestic animals concurrently (p = 0.000), chicken types (p = 0.000) and flock size (p = 0.007) were risk factors for infection in chickens. One hundred and fifty two (152) thermophillic Campylobacter isolates were genotyped by RAPD-PCR of which 114 were C. jejuni (74 from chickens and 40 humans) and 38 C. coli (28 from chickens and 10 humans). Comparison of Campylobacter isolates from children and chickens revealed high diversity with only 6.1% of C. jejuni and 5.3% of C. coli being 100% genetically similar. Conclusions: This study has recorded high prevalence of thermophilic Campylobacter in children less than 5 years and chickens in Morogoro municipality. The observed genetic similarity among few C. jejuni and C. coli isolates from children and chicken suggests existence of cross transmission of these pathogens between children under 5 years and chickens.
Epidemiology and RAPD-PCR typing of thermophilic campylobacters from children under five years and chickens in Morogoro Municipality, Tanzania
(BMC Infectious DiseasesBMC serie, 2016) Chuma, I. S.; Nonga, H. E.; Mdegela, R. H.; Kazwala, R. R.
Campylobacter species are gram negative and flagellated bacteria under the genus Campylobacter, family Campylobacteriaceae. These pathogens cause zoonotic infections among human and animal populations. This study was undertaken between December 2006 and May 2007 to determine prevalence, risk factors and genetic diversity of thermophilic Campylobacter isolates from children less than 5 years and chickens in Morogoro Municipality, Tanzania. Methods
European 1: a globally important clonal complex of Mycobacterium bovis
(ELSEVIER) Smith, N. H.; Berg, S.; Dale, J.; Allen, A.; Rodriguez, S.; Romero, B.; Kazwala, R. R.
European 1: a globally important clonal complex of Mycobacterium bovis
(ELSEVIER, 2011) Smith, N. H.; Berg, S.; Dale, J.; Allen, A.; Rodriguez, S.; Romero, B.; Kazwala, R. R.
We have identified a globally important clonal complex of M. bovis by deletion analysis of over one thousand strains from over 30 countries. We initially show that over 99% of the strains of Mycobacterium bovis, the cause of bovine tuberculosis, isolated from cattle in the Republic of Ireland and the UK are closely related and are members of a single clonal complex marked by the deletion of chromosomal region RDEu,1 and we named this clonal complex European 1 (Eu1). Eu1 strains were present at less than 14% of French, Portuguese and Spanish isolates of M. bovis but are rare in other mainland European countries and Iran. However, strains of the Eu1 clonal complex were found at high frequency in former trading partners of the UK (USA, South Africa, New Zealand, Australia and Canada). The Americas, with the exception of Brazil, are dominated by the Eu1 clonal complex which was at high frequency in Argentina, Chile, Ecuador and Mexico as well as North America. Eu1 was rare or absent in the African countries surveyed except South Africa. A small sample of strains from Taiwan were non-Eu1 but, surprisingly, isolates from Korea and Kazakhstan were members of the Eu1 clonal complex. The simplest explanation for much of the current distribution of the Eu1 clonal complex is that it was spread in infected cattle, such as Herefords, from the UK to former trading partners, although there is evidence of secondary dispersion since. This the first identification of a globally dispersed clonal complex M. bovis and indicates that much of the current global distribution of this important veterinary pathogen has resulted from relatively recent International trade in cattle.
Genetic profile of Mycobacterium tuberculosis and treatment outcomes in human pulmonary tuberculosis in Tanzania
(Tanzania Journal of Health Research) Mfinanga, S. G. M.; Warren, R. M.; Kazwala, R. R.; Kahwa, A.; Kazimoto, T.; Kimaro, G.; Mfaume, S.; Chonde, T.; Ngadaya, E.; Egwaga, S.; Streicher, E. M.; Van Pittius, G. N. C.; Morkve, O.; Cleaveland, S.
Genetic profile of Mycobacterium tuberculosis and treatment outcomes in human pulmonary tuberculosis in Tanzania
(Tanzania Journal of Health Research, 2014-04-02) Mfinanga, S. G. M.; Warren, R. M.; Kazwala, R. R.; Kahwa, A.; Kazimoto, T.; Kimaro, G.; Mfaume, S.; Chonde, T.; Ngadaya, E.; Egwaga, S.; Streicher, E. M.; Van Pittius, G. N. C.; Morkve, O.; Cleaveland, S.
Information on the different spoligotype families of Mycobacterium tuberculosis in Tanzania is limited, and where available, restricted to small geographical areas. This article describes the genetic profile of M. tuberculosis across Tanzania and suggests how spoligotype families might affect drug resistance and treatment outcomes for smear positive pulmonary tuberculosis patients in Tanzania. We conducted the study from 2006 to 2008, and the isolates were obtained from samples collected under the routine drug resistance surveillance system. The isolates were from specimens collected from 2001 to 2007, and stored at the Central and Reference Tuberculosis Laboratory. A total of 487 isolates from 23 regions in the country were spoligotyped. We were able to retrieve clinical information for 446 isolates only. Out of the 487 isolates spoligotyped, 195(40.0%) belonged to the Central Asian (CAS) family, 84 (17.5%) to the Latin American Mediterranean (LAM) family, 49 (10.1%) to the East-African Indian (EAI) family, and 33 (6.8%) to the Beijing family. Other isolates included 1 (0.2%) for H37Rv, 10 (2.1%) for Haarlem, 4 (0.8%) for S family, 58 (11.9%) for T family and 52 (10.7%) for unclassified. No spoligotype patterns were consistent with M. bovis. Regarding treatment outcomes, the cure rate was 80% with no significant variation among the spoligotype families. The overall level of MDR TB was 2.5% (3/121), with no significant difference among the spoligotype families. All Beijing strains (11.8%, 30/254) originated from the Eastern and Southern zones of the country, of which 80% were from Dar es Salaam. Isolates from the CAS and T families were reported disproportionately from the Eastern-Southern zone, and EAI and LAM families from the Northern-Lake zones but the difference was not statistically significant. Five isolates were identified as non-tuberculous Mycobacteria. In conclusion, M. tuberculosis isolates from pulmonary tuberculosis cases in Tanzania were classified mostly within the CAS, LAM, and EAI and T families, while the Beijing family comprised about 7% isolates only. Consistently good treatment outcomes were recorded across these spoligotype families. The proportion of drug resistance strains was low. The findings also suggest variation of spoligotype families with varying geographical localities within the country, and identify this area for further research to confirm this finding.