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1.
Trop Med Infect Dis ; 7(8)2022 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-36006265

RESUMO

Leptospirosis is a zoonotic neglected tropical disease with a worldwide distribution caused by the pathogenic spirochetes of the genus Leptospira. Despite being a widespread disease in tropical regions, it has never been considered in the routine diagnostic panel for febrile patients. This study determined seropositivity and factors associated with Leptospira antibodies among febrile adult patients in Mwanza, Tanzania. The cross-sectional study involving 296 febrile patients attending different outpatient clinics in Mwanza region was conducted between May and July 2019. Detection of Leptospira serovars antibodies was done using a microscopic agglutination test (MAT). Descriptive analysis was done using STATA version 13. The median age of the febrile patients was 32 (IQR: 24-45 years). Out of 296 patients, 36 (12.16%, 95%CI: 8-15) were seropositive for Leptospira antibodies. Common circulating serovars were Sokoine 28 (9.45%), followed by Lora 12 (4.05%) and Grippotyphosa 2 (0.67%). In the multivariable logistic regression analysis, the odds of being Leptospira seropositive were significantly higher with increased age (aOR: 1.03, 95%CI 1.00-1.07, p = 0.03). About one tenth of febrile patients in Mwanza were seropositive for Leptospira antibodies and this was significantly associated with age. With the decline of malaria fever in endemic areas, other causes of febrile illness like Leptospiral spp. should be considered in the routine diagnostic panel for febrile patients.

2.
Acta Trop ; 233: 106566, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35724712

RESUMO

BACKGROUND: Rodents are known to be reservoirs of plague bacteria, Yesinia pestis in the sylvatic cycle. A preliminary investigation of the suspected plague outbreak was conducted in Madunga Ward, Babati District Council in Manyara Region December-2019-January 2020 Following reported two cases which were clinically suspected as showing plague disease symptoms. METHOD: The commensal and field rodents were live trapped using Sherman traps in Madunga Ward, where plague suspect cases were reported and, in the Nou-forest reserve areas at Madunga Ward, Babati District Council, to assess plague risk in the area. Fleas were collected inside the houses using light traps and on the rodents 'body after anaesthetizing the captured rodent to determine flea indices which are used to estimate the risk of plague transmission. Lung impression smears were made from sacrificed rodents to examine for possible bipolar stained Yersinia spp bacilli. RESULTS: A total of 86 rodents consisting of ten rodent species were captured and identified from the study sites. Nine forest rodent species were collected. Field/fallow rodent species were dominated by Mastomys natalensis. whereas domestic rodent species captured was Rattus rattus. Overall lung impression smear showed bipolar stain were 14 (16.28%) while House Flea Index (HFI) was 3.1 and Rodent Flea Index (RFI) was 1.8. CONCLUSION: The findings of this study have shown that, the presence of bipolar stained bacilli in lung impression smears of captured species of rodents indicates (not confirmed) possible circulation of Yesrsinia pests in rodents and the high flea indices in the area which included the most common flea species known to be plague vectors in Tanzania could have played transmission role in this suspected outbreak. The study recommends surveillance follow-up in the area and subject collected samples to the standard plague confirmatory diagnosis.


Assuntos
Peste , Sifonápteros , Animais , Surtos de Doenças , Florestas , Peste/diagnóstico , Peste/epidemiologia , Peste/microbiologia , Ratos , Roedores/microbiologia , Sifonápteros/microbiologia , Tanzânia/epidemiologia
3.
Artigo em Inglês | MEDLINE | ID: mdl-34659646

RESUMO

The diagnosis of tuberculosis (TB) disease remains a global challenge, and the need for innovative diagnostic approaches is inevitable. Trained African giant pouched rats are the scent TB detection technology for operational research. The adoption of this technology is beneficial to countries with a high TB burden due to its cost-effectiveness and speed than microscopy. However, rats with some factors perform better. Thus, more insights on factors that may affect performance is important to increase rats' TB detection performance. This paper intends to provide understanding on the factors that influence rats TB detection performance using visual analytics approach. Visual analytics provide insight of data through the combination of computational predictive models and interactive visualizations. Three algorithms such as Decision tree, Random Forest and Naive Bayes were used to predict the factors that influence rats TB detection performance. Hence, our study found that age is the most significant factor, and rats of ages between 3.1 to 6 years portrayed potentiality. The algorithms were validated using the same test data to check their prediction accuracy. The accuracy check showed that the random forest outperforms with an accuracy of 78.82% than the two. However, their accuracies difference is small. The study findings may help rats TB trainers, researchers in rats TB and Information systems, and decision makers to improve detection performance. This study recommends further research that incorporates gender factors and a large sample size.

4.
Pathogens ; 10(6)2021 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-34205097

RESUMO

BACKGROUND: Leptospirosis is among the major neglected zoonoses in developing countries. The prevalence of leptospirosis remains underestimated in many African countries because of limited diagnostic facilities. We studied Leptospira seropositivity prevalence in humans, sheep, goats and rodents in a semi-arid region of central Tanzania and compared findings with reports from humid tropical areas. The aims were to establish the disease burden in different settings; understand circulating Leptospira serovars and potential major reservoirs for establishing appropriate control measures. METHODS: Humans, sheep, goats, rodents and shrews (insectivores) were sampled from Bahi district, a semi-arid area in central Tanzania. Samples were tested for leptospiral antibodies using microscopic agglutination test (MAT) consisting of Leptospira serovars mainly reported in Tanzania and reference strains. Findings were compared with previous data to determine the disease epidemiological patterns. RESULTS AND CONCLUSION: Semi-arid area showed high Leptospira seropositivity prevalence in humans and domestic animals due to intensive human-animal interactions at scarce water points and by flash flooding which occur in the area. Rodent population in the semi-arid areas was relatively low due to flooding. Leptospira seropositivity in rodents was also slightly lower, and the rodents appeared to be prolific breeders, probably as a means to compensate for the lost population during extreme drought as well as during short spells of floods. Intensive human-animal interaction in the semi-arid areas especially, in water sources in valleys where human and animals often meet, likely increased the risk of leptospirosis transmission to rice farmers in the area. Goats and sheep which are kept around homesteads had higher leptospiral antibodies prevalence (62%), nearly double of the 38% reported in same species in humid tropical regions of Tanzania. Livestock, especially goats and sheep, could be the major source of leptospirosis transmission to humans. Vaccination of livestock with vaccines against local Leptospira strains should be encouraged, and rodent control emphasized, as part of a management strategy against leptospirosis. Public awareness of leptospirosis must also be raised and supported by availability of rapid test kits in clinics for preliminary testing of leptospirosis in people with fevers of unknown origin.

5.
Pathogens ; 10(5)2021 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-34065745

RESUMO

This study investigated seroepidemiology of Leptospira serovars among the dog keepers and their dogs in the city of Mwanza, Tanzania. A total of 205 dog keepers and 414 dogs were tested for Leptospira antibodies using a microscopic agglutination test (MAT). The median age of the dog keepers was 26 (inter quartile range (IQR): 17-40) years and median duration of keeping dogs was 36 (IQR: 24-120) months. The seropositivity of Leptospira antibodies was (33/205 (16.1%, 95% CI: 11.0-21.1) among dog keepers and (66/414 (15.9%, 95% CI: 12.4-19.4) among dogs, p = 0.4745. Among the serovars tested (Sokoine, Grippotyphosa, Kenya, Pomona and Hebdomadis), the most prevalent serovar was Sokoine in both dog keepers and their dogs (93.9% (31/33) vs. and 65.1% (43/66), p = 0.009). Thirty-one out of thirty-three seropositive dog keepers (93.9%) had dogs positive for Leptospira antibodies with 28 (84.9%) having similar serovars with their respective seropositive dogs. Having tertiary education (AOR: 0.24, 95% CI: 0.07-0.84, p = 0.026) independently protected individuals from being Leptospira seropositive. More than three quarters of dog keepers had similar serovars as their dogs, necessitating one health approach to control measures in endemic areas.

6.
Am J Trop Med Hyg ; 103(6): 2552-2560, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33069266

RESUMO

Leptospirosis, brucellosis, and Q fever (coxiellosis) are bacterial zoonoses that cause acute febrile illness in people as well as reproductive losses in pigs. Pig keeping is an increasingly important livelihood to millions of smallholder farmers in Uganda because of exponential increases in demand for pork. The prevalence of leptospirosis and Q fever in pigs is unknown, and the few studies of porcine brucellosis have estimated a range of seroprevalence. Therefore, we undertook a prevalence survey of leptospirosis, brucellosis, and Q fever in pigs using quantitative real-time PCR to determine the potential importance of these zoonoses to the growing pig sector in Uganda. Six hundred forty-nine pigs were sampled in 2015-2016 at an urban pork slaughterhouse. Ten percent of pigs (n = 68) had leptospiral DNA in either their kidney or reproductive tissue. In adjusted analyses, variables predictive of leptospiral status included female sex (odds ratio [OR]: 2.37, P < 0.01) and pigs sampled in March 2016 (OR: 2.23, P = 0.02) and October 2016 (OR: 0.30, P = 0.04). DNA fingerprinting revealed circulation of at least four distinct serovars in these pigs. Brucella spp. and Coxiella burnetii DNA were not detected in any sampled pig. This is the first report of widespread circulation of pathogenic Leptospira spp. in pigs in Uganda, suggesting that leptospirosis likely has a greater impact on the health of pigs than was previously recognized. Pig farmers, pig traders, and slaughterhouse workers may be at greatest occupational risk because of their direct contact with infective leptospires in aborted fetuses, bodily fluids, and other tissues.


Assuntos
Brucelose/veterinária , Doenças Endêmicas/veterinária , Leptospirose/veterinária , Febre Q/veterinária , Doenças dos Suínos/microbiologia , Animais , Brucelose/epidemiologia , Estudos Transversais , Coleta de Dados , Feminino , Leptospira/classificação , Leptospirose/epidemiologia , Leptospirose/microbiologia , Masculino , Febre Q/epidemiologia , Reação em Cadeia da Polimerase em Tempo Real/veterinária , Fatores de Risco , Suínos , Doenças dos Suínos/epidemiologia , Uganda/epidemiologia , Zoonoses
8.
BMC Vet Res ; 15(1): 403, 2019 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-31703588

RESUMO

BACKGROUND: Leptospirosis is a neglected zoonosis of public health importance transmitted through contact with contaminated soil, water or urine of infected animals. In pigs the disease is characterized by abortion, still births and weak piglets. A cross-sectional study was conducted in May to July 2018 to estimate the sero-prevalence of leptospirosis and factors associated with seropositivity in slaughter pigs. A questionnaire was used to collect information on animal demographics. Serum was tested for anti-leptospiral antibodies using microscopic agglutination test (MAT) with a panel of 8 serovars. Sera were considered positive for sero-reactivity at a MAT titre ≥1:40 against at least one serovar. Chi-square tests were used to measure the strength of association between the MAT test result and exploratory variables. RESULTS: A total of 252 pig serum samples from seven slaughterhouses were tested for Leptospira antibodies by MAT. Of the 252 pigs sampled, 88.8% (244/252) were indigenous breeds; 55.6% (140/252) were female and 88.7% (220/252) were reared in extensive production systems. Eighty-three (32.9%; 83/252) sera samples tested positive on MAT against at least one serovar. Of the 8 serovars, the highest prevalence was recorded for serovar Lora 21.4% followed by Kenya 5.2%, Sokoine 3.6% and Grippotyphosa at 3.2%. Risk factors for leptospirosis seropositivity in pigs were: originating from farms with other types of livestock (OR 2.3; 95% CI 1.0-4.5) and mature pigs (OR 1.9; 95% CI 1.1-3.3). CONCLUSION: This study demonstrates that there is a high prevalence of leptospirosis positive pigs at slaughter in a small-holder livestock keeping region of the Lake Victoria basin. The potential for cross species transmission of pathogenic serovars is highlighted as well as the potential for occupational exposure to slaughterhouse personnel. Improvements in husbandry practices (confinement and rodent control) and public health education among slaughterhouse workers and other high-risk groups is recommended.


Assuntos
Leptospirose/veterinária , Estudos Soroepidemiológicos , Doenças dos Suínos/microbiologia , Matadouros , Criação de Animais Domésticos , Animais , Estudos Transversais , Feminino , Quênia/epidemiologia , Leptospira/imunologia , Leptospira/isolamento & purificação , Leptospirose/epidemiologia , Leptospirose/imunologia , Masculino , Fatores de Risco , Suínos , Doenças dos Suínos/imunologia , Zoonoses
9.
PLoS Negl Trop Dis ; 13(5): e0007225, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-31150391

RESUMO

BACKGROUND: Leptospirosis is a bacterial zoonotic disease of worldwide importance, though relatively neglected in many African countries including sub Saharan Africa that is among areas with high burden of this disease. The disease is often mistaken for other febrile illnesses such as dengue, malaria, rickettsioses and enteric fever. Leptospirosis is an occupational disease likely to affect people working in environments prone to infestation with rodents which are the primary reservoir hosts of this disease. Some of the populations at risk include: sugarcane plantation workers, wetland farmers, fishermen and abattoir workers. In this study we investigated the prevalence of antibodies against Leptospira among sugarcane plantation and factory workers, fishing communities as well as among rodents and shrews in domestic and peridomestic environments within the study areas. METHODS: The study was conducted in Kagera region, northwestern Tanzania and it involved sugarcane plantation workers (cutters and weeders), sugar factory workers and the fishing community at Kagera Sugar Company in Missenyi district and Musira island in Lake Victoria, Kagera, respectively. Blood was collected from consenting human adults, and from rodents and shrews (insectivores) captured live using Sherman traps. Serological detection of leptospiral antibodies in blood serum was carried out by the microscopic agglutination test (MAT). RESULTS: A total of 455 participants were recruited from the sugarcane plantation (n = 401) and fishing community (n = 54) while 31 rodents and shrews were captured. The overall prevalence of antibodies against Leptospira in human was 15.8%. Sugarcane cutters had higher seroprevalence than other sugar factory workers. Prevalent antibodies against Leptospira serovars in humans were against serovars Lora (6.8%), Sokoine (5.3%), Pomona (2.4%), Hebdomadis (1.1%) and Kenya (0.2%). Detected leptospiral serovars in reservoir hosts were Sokoine (12.5%) and Grippotyphosa (4.2%). Serovar Sokoine was detected both in humans and small mammals. CONCLUSION: Leptospirosis is a public health threat affecting populations at risk, such as sugarcane plantation workers and fishing communities. Public awareness targeting risk occupational groups is much needed for mitigation of leptospirosis in the study areas and other vulnerable populations in Tanzania and elsewhere.


Assuntos
Leptospirose/microbiologia , Adolescente , Adulto , Animais , Anticorpos Antibacterianos/sangue , Reservatórios de Doenças/microbiologia , Fazendeiros/estatística & dados numéricos , Feminino , Pesqueiros , Humanos , Leptospira/classificação , Leptospira/genética , Leptospira/imunologia , Leptospira/isolamento & purificação , Leptospirose/sangue , Leptospirose/epidemiologia , Leptospirose/transmissão , Masculino , Pessoa de Meia-Idade , Prevalência , Roedores/imunologia , Roedores/microbiologia , Saccharum/crescimento & desenvolvimento , Estudos Soroepidemiológicos , Musaranhos/imunologia , Musaranhos/microbiologia , Tanzânia/epidemiologia , Adulto Jovem , Zoonoses/sangue , Zoonoses/microbiologia
10.
Science ; 364(6443): 852-859, 2019 05 31.
Artigo em Inglês | MEDLINE | ID: mdl-31147513

RESUMO

Noxious substances, called algogens, cause pain and are used as defensive weapons by plants and stinging insects. We identified four previously unknown instances of algogen-insensitivity by screening eight African rodent species related to the naked mole-rat with the painful substances capsaicin, acid (hydrogen chloride, pH 3.5), and allyl isothiocyanate (AITC). Using RNA sequencing, we traced the emergence of sequence variants in transduction channels, like transient receptor potential channel TRPA1 and voltage-gated sodium channel Nav1.7, that accompany algogen insensitivity. In addition, the AITC-insensitive highveld mole-rat exhibited overexpression of the leak channel NALCN (sodium leak channel, nonselective), ablating AITC detection by nociceptors. These molecular changes likely rendered highveld mole-rats immune to the stings of the Natal droptail ant. Our study reveals how evolution can be used as a discovery tool to find molecular mechanisms that shut down pain.


Assuntos
Evolução Molecular , Ratos-Toupeira/fisiologia , Canal de Sódio Disparado por Voltagem NAV1.7/genética , Dor Nociceptiva/genética , Limiar da Dor , Canal de Cátion TRPA1/genética , Animais , Sítios de Ligação , Capsaicina/farmacologia , Ácido Clorídrico/farmacologia , Mordeduras e Picadas de Insetos/genética , Mordeduras e Picadas de Insetos/imunologia , Isotiocianatos/farmacologia , Ratos-Toupeira/genética , Ratos-Toupeira/imunologia , Dor Nociceptiva/induzido quimicamente , Nociceptores/efeitos dos fármacos , Nociceptores/fisiologia , Conformação Proteica , Análise de Sequência de RNA , Especificidade da Espécie , Canal de Cátion TRPA1/química
11.
PLoS Negl Trop Dis ; 12(6): e0006600, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29939991

RESUMO

INTRODUCTION: Brucellosis and leptospirosis are among neglected tropical zoonotic diseases particularly in the resource limited countries. Despite being endemic in these countries, there is paucity of information on its magnitude. This study investigated seropositivity of Brucella spp. and Leptospira spp., and associated factors among abattoir workers and meat vendors in the city of Mwanza, Tanzania. METHODOLOGY: A community based cross-sectional study was conducted in Mwanza city from May to July 2017. Socio-demographic and other relevant information were collected. Detection of Brucella spp. and Leptospira spp. antibodies were done using slide agglutination test and microscopic agglutination test, respectively. Data were analyzed using STATA version 13 Software. FINDINGS: A total of 250 participants (146 abattoir workers and 104 meat vendors) were enrolled with median age of 31 (IQR: 25-38) years. The overall, seropositivity of Brucella spp. antibodies was 48.4% (95% Cl: 42-54). Seropositivity of B. abortus was significantly higher than that of B. melitensis (46.0%, 95%Cl: 39-52 vs. 23.6%, 95% Cl: 18-28, P<0.001) while seropositivity of both species was 21.2% (95%Cl: 16-26). The seropositivity of Leptospira spp. was 10.0% (95% CI: 6-13) with predominance of Leptospira kirschneri serovar Sokoine which was detected in 7.2% of the participants. Being abattoir worker (OR: 2.19, 95% CI 1.06-4.54, p = 0.035) and long work duration (OR: 1.06, 95%CI: 1.01-1.11, p = 0.014) predicted presence of both B.abortus and B. melitensis antibodies. Only being married (p = 0.041) was significantly associated with seropositivity of Leptospira spp. Primary education was the only factor independently predicted presence of Brucella spp. antibodies among abattoir workers on sub-analysis of occupational exposure. None of factors were found to be associated with presence of Brucella spp. antibodies among meat vendors on sub-analysis. CONCLUSION: Seropositivity of B.abortus antibodies among abattoir workers and meat vendors is high and seem to be a function of being abattoir worker, having worked for long duration in the abattoir and having primary education. In addition, a significant proportion of abattoir workers and meat vendors in the city was seropositive for Leptospira kirschneri serovar Sokoine. There is a need to consider 'one health approach' in devising appropriate strategies to control these diseases in the developing countries.


Assuntos
Anticorpos Antibacterianos/sangue , Brucella/imunologia , Brucelose/epidemiologia , Leptospira/imunologia , Leptospirose/epidemiologia , Doenças Negligenciadas/epidemiologia , Exposição Ocupacional , Matadouros , Adulto , Testes de Aglutinação , Brucella/isolamento & purificação , Brucelose/microbiologia , Brucelose/prevenção & controle , Estudos Transversais , Feminino , Humanos , Leptospira/isolamento & purificação , Leptospirose/microbiologia , Leptospirose/prevenção & controle , Masculino , Doenças Negligenciadas/microbiologia , Doenças Negligenciadas/prevenção & controle , Saúde Única , Estudos Soroepidemiológicos , Tanzânia/epidemiologia
13.
Pediatr Res ; 84(1): 99-103, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29617007

RESUMO

BACKGROUND: Tuberculosis (TB) diagnosis in children is a challenge with up to 94% of children with TB treated empirically in TB high-burden countries. Therefore, new diagnostic tests are needed for TB diagnosis. We determined the performance of trained rats in the diagnosis of pediatric TB and whether they can improve detection rate compared to the standard of care. METHODS: Presumptive TB patients in 24 TB clinics in Tanzania were tested. Samples indicated as TB-positive by rats underwent confirmation by concentrated smear microscopy. TB yield of bacteriologically confirmed pediatric TB patients (≤5 years) was compared with yield of standard of care. RESULTS: Sputum samples from 55,148 presumptive TB patients were tested. Nine hundred eighty-two (1.8%) were the children between 1 and 5 years. Clinics detected 34 bacteriologically positive children, whereas rats detected additional 23 children yielding 57 bacteriologically TB-positive children. Rats increased pediatric TB detection by 67.6%. Among 1-14-year-old children, clinics detected 331 bacteriologically positive TB whereas rats found the additional 208 children with TB that were missed by clinics. Relative increase in TB case detection by rats decreased with the increase in age (P<0.0001). CONCLUSION: Trained rats increase pediatric TB detection significantly and could help address the pediatric TB diagnosis challenges. Further determination of accuracy of rats involving other sample types is still needed.


Assuntos
Técnicas de Laboratório Clínico/métodos , Testes Diagnósticos de Rotina/normas , Roedores , Tuberculose/diagnóstico , Adolescente , Animais , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Programas de Rastreamento/métodos , Microscopia , Mycobacterium tuberculosis , Odorantes , Pediatria/métodos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Olfato , Escarro , Tanzânia , Compostos Orgânicos Voláteis
14.
Behav Processes ; 155: 2-7, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28554740

RESUMO

Giant African pouched rats (Cricetomys ansorgei) have been employed successfully in two operational tuberculosis-detection projects in which they sniff sputum samples from symptomatic individuals who have visited tuberculosis clinics. The prevalence of pulmonary tuberculosis in this population is high, approximately 20% in the regions where the rats have been used. If the rats are to be used to screen individuals from lower-prevalence populations, their performance under such conditions must first be evaluated. In this study, the prevalence of tuberculosis-positive samples presented to eight pouched rats was reduced to approximately 5%, and the percentage of known-positive samples included as opportunities for reinforcement was varied in sequence from 10 to 8, 6, 4, 2, 4, and 2. Liquid food reinforcers were delivered for identification responses to known-positive samples and at no other time. The rats' accuracy was clinically and statistically significantly lower at 2% than at the other values. These results indicate that the rats can perform well in low-prevalence scenarios but, if they are used under the conditions of the present study, at least 4% of the samples presented to them must be opportunities for reinforcement.


Assuntos
Técnicas e Procedimentos Diagnósticos , Muridae/fisiologia , Olfato/fisiologia , Tuberculose/diagnóstico , Tuberculose/epidemiologia , Animais , Condicionamento Operante , Feminino , Alimentos , Humanos , Individualidade , Prevalência , Desempenho Psicomotor , Reforço Psicológico , Escarro
16.
PeerJ ; 5: e3214, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28462027

RESUMO

Previous studies of African mole-rats of the genera Heliophobius and Fukomys (Bathyergidae) in the regions of East and south central Africa have revealed a diversity of species and vicariant populations, with patterns of distribution having been influenced by the geological process of rifting and changing patterns of drainage of major river systems. This has resulted in most of the extant members of the genus Fukomys being distributed west of the main Rift Valley. However, a small number of isolated populations are known to occur east of the African Rift Valley in Tanzania, where Heliophobius is the most common bathyergid rodent. We conducted morphological, craniometric and phylogenetic analysis of mitochondrial cytochrome b (cyt b) sequences of two allopatric populations of Tanzanian mole-rats (genus Fukomys) at Ujiji and around Mount Hanang, in comparison with both geographically adjacent and more distant populations of Fukomys. Our results reveal two distinct evolutionary lineages, forming clades that constitute previously unnamed species. Here, we formally describe and designate these new species F. livingstoni and F. hanangensis respectively. Molecular clock-based estimates of divergence times, together with maximum likelihood inference of biogeographic range evolution, offers strong support for the hypothesis that vicariance in the Western Rift Valley and the drainage patterns of major river systems has subdivided populations of mole-rats. More recent climatic changes and tectonic activity in the "Mbeya triple junction" and Rungwe volcanic province between Lakes Rukwa and Nyasa have played a role in further isolation of these extra-limital populations of Fukomys in Tanzania.

17.
J Appl Behav Anal ; 50(1): 165-169, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-27718224

RESUMO

Tuberculosis (TB) is a major problem in poor countries because sensitive diagnostic tools are unavailable. In 2014, our pouched rats evaluated sputum from 21,600 Tanzanians and 9,048 Mozambicans whose sputum had previously been evaluated by microscopy, the standard diagnostic for TB. Evaluation by the rats revealed 1,412 new patients with active TB in Tanzania and 645 new patients in Mozambique, increases of 39% and 53%, respectively, when compared to detections by microscopy alone. These results provide further support for the applied use of scent-detecting rats.


Assuntos
Programas de Rastreamento/métodos , Mycobacterium tuberculosis/isolamento & purificação , Tuberculose/diagnóstico , Tuberculose/epidemiologia , Animais , Estudos de Coortes , Técnicas e Procedimentos Diagnósticos , Feminino , Humanos , Masculino , Moçambique/epidemiologia , Ratos , Tanzânia/epidemiologia
18.
PLoS Negl Trop Dis ; 9(12): e0004251, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26624890

RESUMO

The burden of leptospirosis in humans and animals in Africa is higher than that reported from other parts of the world. However, the disease is not routinely diagnosed in the continent. One of major factors limiting diagnosis is the poor availability of live isolates of locally circulating Leptospira serovars for inclusion in the antigen panel of the gold standard microscopic agglutination test (MAT) for detecting antibodies against leptospirosis. To gain insight in Leptospira serovars and their natural hosts occurring in Tanzania, concomitantly enabling the improvement of the MAT by inclusion of fresh local isolates, a total of 52 Leptospira isolates were obtained from fresh urine and kidney homogenates, collected between 1996 and 2006 from small mammals, cattle and pigs. Isolates were identified by serogrouping, cross agglutination absorption test (CAAT), and molecular typing. Common Leptospira serovars with their respective animal hosts were: Sokoine (cattle and rodents); Kenya (rodents and shrews); Mwogolo (rodents); Lora (rodents); Qunjian (rodent); serogroup Grippotyphosa (cattle); and an unknown serogroup from pigs. Inclusion of local serovars particularly serovar Sokoine in MAT revealed a 10-fold increase in leptospirosis prevalence in Tanzania from 1.9% to 16.9% in rodents and 0.26% to 10.75% in humans. This indicates that local serovars are useful for diagnosis of human and animal leptospirosis in Tanzania and other African countries.


Assuntos
Anticorpos Antibacterianos/sangue , Reservatórios de Doenças , Leptospira/classificação , Leptospirose/diagnóstico , Leptospirose/veterinária , Sorogrupo , África/epidemiologia , Testes de Aglutinação , Animais , Humanos , Rim/microbiologia , Leptospira/isolamento & purificação , Leptospirose/microbiologia , Mamíferos , Tipagem Molecular , Prevalência , Urina/microbiologia
19.
Pan Afr Med J ; 21: 333, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26587178

RESUMO

Despite its characteristically low sensitivity, sputum smear microscopy remains the standard for diagnosing tuberculosis (TB) in resource-poor countries. In an attempt to develop an alternative or adjunct to microscopy, researchers have recently examined the ability of pouched rats to detect TB-positive human sputum samples and the microbiological variables that affect their detection. Ten published studies, reviewed herein, suggest that the rats are able to detect the specific odor of Mycobacterium tuberculosis, which causes TB, and can substantially increase new-case detections when used for second-line TB screening following microscopy. Further research is needed to ascertain the rats' ability to detect TB in children and in HIV-positive patients, to detect TB when used for first-line screening, and to be useful in broad-scale applications where cost-effectiveness is a major consideration.


Assuntos
Mycobacterium tuberculosis/isolamento & purificação , Escarro/microbiologia , Tuberculose/diagnóstico , Animais , Técnicas e Procedimentos Diagnósticos , Humanos , Programas de Rastreamento/métodos , Microscopia/métodos , Odorantes , Roedores , Tuberculose/microbiologia
20.
Curr Microbiol ; 70(2): 212-8, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25274413

RESUMO

Tuberculosis (TB) diagnosis in low-income countries is mainly done by microscopy. Hence, little is known about the diversity of Mycobacterium spp. in TB infections. Different genotypes or lineages of Mycobacterium tuberculosis vary in virulence and induce different inflammatory and immune responses. Trained Cricetomys rats show a potential for rapid diagnosis of TB. They detect over 28 % of smear-negative, culture-positive TB. However, it is unknown whether these rats can equally detect sputa from patients infected with different genotypes of M. tuberculosis. A 4-month prospective study on diversity of Mycobacterium spp. was conducted in Dar es Salaam, Tanzania. 252 sputa from 161 subjects were cultured on Lowenstein-Jensen medium and thereafter tested by rats. Mycobacterial isolates were subjected to molecular identification and multispacer sequence typing (MST) to determine species and genotypes. A total of 34 Mycobacterium spp. isolates consisting of 32 M. tuberculosis, 1 M. avium subsp. hominissuis and 1 M. intracellulare were obtained. MST analyses of 26 M. tuberculosis isolates yielded 10 distinct MST genotypes, including 3 new genotypes with two clusters of related patterns not grouped by geographic areas. Genotype MST-67, shared by one-third of M. tuberculosis isolates, was associated with the Mwananyamala clinic. This study shows that diverse M. tuberculosis genotypes (n = 10) occur in Dar es Salaam and trained rats detect 80 % of the genotypes. Sputa with two M. tuberculosis genotypes (20 %), M. avium hominissuis and M. intracellulare were not detected. Therefore, rats detect sputa with different M. tuberculosis genotypes and can be used to detect TB in resource-poor countries.


Assuntos
Genótipo , Mycobacterium/classificação , Mycobacterium/genética , Tuberculose Pulmonar/microbiologia , Adolescente , Adulto , Animais , Criança , Pré-Escolar , Feminino , Geografia Médica , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Tipagem de Sequências Multilocus , Filogenia , Estudos Prospectivos , Ratos , Escarro/microbiologia , Tanzânia , Tuberculose Pulmonar/diagnóstico , Adulto Jovem
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