60 research outputs found
Leptospira Serovars for Diagnosis of Leptospirosis in Humans and Animals in Africa: Common Leptospira Isolates and Reservoir Hosts
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 neighbouring countries
Building an African Leptospirosis Network
Although leptospirosis is a disease of global importance, local context is crucial to formulating effective intervention strategies. Factors including reservoir host species, pathogen type, environmental, and social settings generate context-specific epidemiologies. Diverse climatic zones, agricultural systems, urbanization patterns, and cultural practices in Africa are likely to drive considerable variation in leptospirosis epidemiology. There is growing evidence of a substantial burden of human leptospirosis in Africa that is difficult to quantify in part due to lack of surveillance and clinical awareness of leptospirosis. Leptospirosis is therefore rarely considered as a differential diagnosis for acute febrile illness, and there is little access to diagnostic services for leptospirosis on the continent. In 2016, a virtual network was founded focussing on improving awareness and understanding leptospirosis in Africa. We currently have 40 members from academia, clinical practice, government and non-governmental agencies and others. Current members are based predominantly in institutions outside the continent but increasingly colleagues based in public health, laboratories, veterinary, and academic institutions within Africa are joining. We will share our experiences of developing this network, and our plans for capacity building through identifying and addressing knowledge gaps in our understanding of leptospirosis in Africa
Isolation and Characterization of New Leptospira Genotypes from Patients in Mayotte (Indian Ocean)
Leptospirosis has been recognized as an increasing public health problem affecting poor people from developing countries and tropical regions. However, the epidemiology of leptospirosis remains poorly understood in remote parts of the world. In this study of patients from the island of Mayotte, we isolated 22 strains from the blood of patients during the acute phase of illness. The pathogenic Leptospira strains were characterized by serology and various molecular typing methods. Based on serological data, serogroup Mini appears to be the dominant cause of leptospirosis in Mayotte. Further molecular characterization of these isolates allowed the identification of 10 pathogenic Leptospira genotypes that could correspond to previously unknown serovars. Further progress in our understanding of the epidemiology of Leptospira circulating genotypes in highly endemic regions should contribute to the development of novel strategies for the diagnosis and prevention of this neglected emerging disease
Profiles of Volatile Biomarkers Detect Tuberculosis from Skin
Tuberculosis (TB) is an infectious disease that threatens >10 million people annually. Despite advances in TB diagnostics, patients continue to receive an insufficient diagnosis as TB symptoms are not specific. Many existing biodiagnostic tests are slow, have low clinical performance, and can be unsuitable for resource-limited settings. According to the World Health Organization (WHO), a rapid, sputum-free, and cost-effective triage test for real-time detection of TB is urgently needed. This article reports on a new diagnostic pathway enabling a noninvasive, fast, and highly accurate way of detecting TB. The approach relies on TB-specific volatile organic compounds (VOCs) that are detected and quantified from the skin headspace. A specifically designed nanomaterial-based sensors array translates these findings into a point-of-care diagnosis by discriminating between active pulmonary TB patients and controls with sensitivity above 90%. This fulfills the WHO's triage test requirements and poses the potential to become a TB triage test
Application of a multidisciplinary approach to the systematics of Acomys (Rodentia: Muridae) from Northern Tanzania
The systematic status and geographic distribution of spiny mice of the genus Acomys I.
Geoffroy, 1838 in Northern Tanzania is uncertain. This study assesses the systematic and
geographic distribution of Acomys from Northern Tanzania using a multidisciplinary
approach that includes molecular, cytogenetic, traditional and geometric morphometric
analyses, and classical morphology of the same individuals. The molecular analysis was
based on 1140 base pairs (bp) of the mitochondrial cytochrome b and 1297 bp of the
nuclear interphotoreceptor retinoid binding protein (IRBP) gene sequences. These data
were subjected to phylogenetic analyses using Maximum likelihood, Bayesian, Maximum
parsimony, and Minimum evolution analyses. The cytogenetic analysis included G-banding
of metaphase chromosomes. The morphometric analyses included univariate and
multivariate analyses of traditional morphometric measurements of the cranium and
mandible, and of geometric morphometric two-dimensional landmarks of the dorsal,
ventral, and lateral views of the cranium, and lateral view of mandible that included thinplate
spline (TPS) analysis. The classical morphology included examination of external,
cranial and mandibular morphology. Results of all these multidisciplinary analyses were
congruent and provide evidence for the occurrence of two sympatric species of Acomys in
northern Tanzania, namely, the previously recorded A. wilsoni (2n = 62) and a newly
recorded A. cf. percivali (2n = 58). These results that also represent the first reported
mitochondrial cytochrome b and nuclear IRBP gene sequences and karyotype for A. cf.
percivali, increases the number of species known to occur in Tanzania from four to five.
However, the mitochondrial cytochrome b data that included GenBank sequences from the
type locality in Kenya suggest that A. wilsoni may not be monophyletic. Ecologically, the
two species seem to partition their niches with A. cf. percivali being found in well-covered
habitats with thorn bushes, rocky and mountainous areas, and A. wilsoni being found in
open semi-arid grasslands as well as in rice fields. The two species appear to be isolated by
complex natural barriers formed by the Great East African Rift Valley whose geological
features have generally been associated with active rodent speciation. However, the present
results need further multidisciplinary investigation involving extensive sampling and
examination of topotypical material
Application of a multidisciplinary approach to the systematics of Acomys (Rodentia: Muridae) from Northern Tanzania
The systematic status and geographic distribution of spiny mice of the genus Acomys I.
Geoffroy, 1838 in Northern Tanzania is uncertain. This study assesses the systematic and
geographic distribution of Acomys from Northern Tanzania using a multidisciplinary
approach that includes molecular, cytogenetic, traditional and geometric morphometric
analyses, and classical morphology of the same individuals. The molecular analysis was
based on 1140 base pairs (bp) of the mitochondrial cytochrome b and 1297 bp of the
nuclear interphotoreceptor retinoid binding protein (IRBP) gene sequences. These data
were subjected to phylogenetic analyses using Maximum likelihood, Bayesian, Maximum
parsimony, and Minimum evolution analyses. The cytogenetic analysis included G-banding
of metaphase chromosomes. The morphometric analyses included univariate and
multivariate analyses of traditional morphometric measurements of the cranium and
mandible, and of geometric morphometric two-dimensional landmarks of the dorsal,
ventral, and lateral views of the cranium, and lateral view of mandible that included thinplate
spline (TPS) analysis. The classical morphology included examination of external,
cranial and mandibular morphology. Results of all these multidisciplinary analyses were
congruent and provide evidence for the occurrence of two sympatric species of Acomys in
northern Tanzania, namely, the previously recorded A. wilsoni (2n = 62) and a newly
recorded A. cf. percivali (2n = 58). These results that also represent the first reported
mitochondrial cytochrome b and nuclear IRBP gene sequences and karyotype for A. cf.
percivali, increases the number of species known to occur in Tanzania from four to five.
However, the mitochondrial cytochrome b data that included GenBank sequences from the
type locality in Kenya suggest that A. wilsoni may not be monophyletic. Ecologically, the
two species seem to partition their niches with A. cf. percivali being found in well-covered
habitats with thorn bushes, rocky and mountainous areas, and A. wilsoni being found in
open semi-arid grasslands as well as in rice fields. The two species appear to be isolated by
complex natural barriers formed by the Great East African Rift Valley whose geological
features have generally been associated with active rodent speciation. However, the present
results need further multidisciplinary investigation involving extensive sampling and
examination of topotypical material
Pediatric tuberculosis detection using trained African giant pouched rats
Article of Basic Science Volume 84 | Number 1 | July 2018, pg. 99-103BACKGROUND: 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 (Po0.0001).
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
Leptospira infections in freshwater fish in Morogoro Tanzania: a hidden public health threat
Tanzania journal of health research 2014; 16 (2):Leptospirosis caused by spirochete bacterium of genus Leptospira affects humans and animals
worldwide. Rodents are major reservoirs of leptospires whereas wetland and aquatic migratory birds also
carry and transmit leptospires. Leptospirosis studies in fish are lacking in African countries despite
favourable environment and abundant reservoirs, which can spread leptospires into aquatic habitats and
infect fish. The objectives of this study were to determine presence of Leptospira in fish; the prevalent
Leptospira serovars and whether are related to serovars reported in animals; and to ascertain potential
public health risk. Live tilapia, catfish and eel fish (n=48) were caught in Mindu Dam in Morogoro
Municipality in eastern Tanzania. Blood sample was collected using syringes and needles to obtain serum
for serological detection of leptospirosis using gold standard microagglutination test utilizing local and
reference Leptospira serovars Sokoine, Kenya, Pomona and Hebdomadis. Twenty-six fish (54.2%) were
positive for serovar Kenya (29.2%) and Sokoine (25%). Leptospira prevalence was high in both catfish (58.3%)
and tilapia fish (47.8%). Thus, different fish types are infected with Leptospira found in animals. Fish could
be source of Leptospira infection to humans since tilapia and catfish are the common fish type widely
consumed in Tanzania. Further study covering lakes, rivers and dams is required to better understand the
prevalence of Leptospira in fish and actual public health threats
Short communication - effects of azadirachta indica (neem) extract on livestock fleas in Morogoro district, Tanzania
Aqueous neem seed kernels extracts (NSKE) were used to treat flea-infested goats in Morogoro, Tanzania to determine their efficacy for flea control. Mean population densities of the insects were significantly lower in the treated goats compared to their untreated counterparts (P < 0.05). It was concluded that NSKE has potential in controlling livestock fleas, but further studies are needed to determine the active principals against fleas and their mode of action
Seroprevalence of Leptospira infection in bats roosting in human settlements in Morogoro municipality in Tanzania
Tanzania Journal of Health Research V 16(1) January 2014Leptospirosis is a neglected emerging infectious disease with high burden in Africa. Major
reservoirs of leptospirosis are rodents and other small mammals. Studies of leptospirosis in bats and the
extent to which they contribute to its transmission to humans and domestic animals in Tanzania are
lacking. The objective of this study was to determine the prevalence of leptospirosis and local Leptospira
serovars in bat colonies found around human settlements in Morogoro, Tanzania. In this study, mist nets
were used to capture bats at Sokoine University of Agriculture main campus, whereas bats roosting on
trees at Nunge A, Nunge B and Mwere primary school were captured manually. Leptospirosis was
determined using the gold standard microscopic agglutination test for determination of Leptospira
antibodies. Six live Leptospira serovars including local Leptospira serovar Sokoine, Kenya and Lora reported
in rodents and domestic animals in Tanzania, and reference serovars Hebdomadis, Canicola and Pomona
were used in the study. Leptospirosis prevalence was high in bats (19.4%) and higher within colonies
(27.3%). Leptospira serovar Sokoine was more prevalent (19.4%) compared to serovars Kenya (2.8%) and
Lora (2.8%). Serovars Pomona, Canicola and Hebdomadis were not detected in bats. In conclusion, bats are
potential reservoir and transmitter of Leptospira serovar Sokoine, hence should be prevented to access
houses and roosting in human settlements to avoid public health risks. Routine diagnosis of human
leptospirosis is needed in Tanzania as evidence show a high prevalence of Leptospira in reservoir hosts
interacting with humans
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