Identification of Plague Hosts and Vectors in Lushoto District of Tanzania.

Plague is a zoonotic disease, endemic throughout the world except Australia and Antarctica. In Africa the disease has been reported in countries such as Democratic Republic of Congo, Madagascar, Mozambique, Uganda and the United Republic of Tanzania. Surveillance work done in Mbulu and Karatu plague foci revealed the evidence of Yersinia pestis in rodents despite lack of disease outbreaks. The information obtained prompted a study to be done in another plague focus of Lushoto. In this study live trapping of wild and commensal rodents was done after which fleas were collected. Nine rodent species of captured and these includes Mastomys (33%), Rattus rattus (25.9%), Praomys (14.3%), Lophuromys (14.3%), Grammomys (8%), Beamys (1.8%), Arvicanths (0.9%), Croccidura (1.8%) and Mus (0.9%). Of the rodents identified Mastomys (33%), Rattus rattus (25.9%), Arvicanths (0.9%), and Mus (0.9%

Spatio-temporal patterns in the distribution of the multi-mammate mouse, Mastomys natalensis, in rice crop and fallow land habitats in Tanzania

An understanding of the dispersion patterns of a pest is an important pre-requisite for developing an effective management programme for the pest. In this study, rodents were trapped in two rice fields and two fallow fields for three consecutive nights each month from June 2010 to May 2012. Mastomys natalensis was the most abundant rodent pest species in the study area, accounting for > 95% of the trapped rodent community. Rattus rattus, Dasymys incomtus, Acomys spinosissimus and Grammomys dolichurus comprised relatively small proportions of the trapped population. Morisita’s index of dispersion was used to measure the relative dispersal pattern aggregate, random, uniform) of individuals across each trapping grid as a means of comparing rodent distribution in rice and fallow fields over time. This analysis revealed that the rodents in rice fields generally exhibited an aggregated spatio-temporal distribution. However, the rodents in fallow fields were generally less aggregated, approaching a random distribution in some habitats and seasons. Heat maps of trapping grids visually confirmed these dispersal patterns, indicating the clumped or random nature of captured rodents. ANOVA showed that the parameters of habitat (rice, fallow), crop stage (transplanting, vegetative, booting, maturity) and cropping season (wet, dry) all significantly impacted the number of rodents captured, with the vegetative, dry season, fallow habitat having the highest number of rodents; and the transplanting, wet season, rice habitat with the least number of rodents. Therefore, such spatio-temporal patterns can serve as a tool for developing stratified biodiversity sampling plans for small mammals and decision making for rodent pest management strategies

Survival and recruitment of the multimammate mouse, Mastomys natalensis (Smith 1834), in a rice agro-ecosystem

We investigated the recruitment and survival of the multimammate mouse, Mastomys natalensis, within irrigated rice and fallow field habitats at different time periods related to rice crop growth stages. Capture-Mark-Recapture data were collected for M . natalensis each month from June 2010 to May 2012, and both recruitment and survival were estimated in relation to land use (irrigated rice or fallow field) within the agro-ecosystem. Higher recruitment and survival were observed in rice fields than in fallow fields suggesting the relationship was compensatory when there was a higher quality food resource. In terms of management, farmers in the study area should implement management strategies in rice fields at both transplanting and maturity stages of crop growth in order to maintain recruitment and survival at low levels

Evidence of Yersinia pestis DNA from fleas in an endemic plague area of Zambia

BACKGROUND: Yersinia pestis is a bacterium that causes plague which infects a variety of mammals throughout the world. The disease is usually transmitted among wild rodents through a flea vector. The sources and routes of transmission of plague are poorly researched in Africa, yet remains a concern in several sub-Saharan countries. In Zambia, the disease has been reported on annual basis with up to 20 cases per year, without investigating animal reservoirs or vectors that may be responsible in the maintenance and propagation of the bacterium. In this study, we undertook plague surveillance by using PCR amplification of the plasminogen activator gene in fleas. FINDINGS: Xenopsylla species of fleas were collected from 83 rodents trapped in a plague endemic area of Zambia. Of these rodents 5 had fleas positive (6.02%) for Y. pestis plasminogen activator gene. All the Y. pestis positive rodents were gerbils. CONCLUSIONS: We conclude that fleas may be responsible in the transmission of Y. pestis and that PCR may provide means of plague surveillance in the endemic areas of Zambia

Knowledge and attitudes of communities on small mammalian carnivores in Mbomipa wildlife management area, Iringa, Tanzania

African Journal of Science and Research, 2015, (4)6:43-46The term Wildlife Management Area (WMA) refers to an area set aside by village governments and gazetted by the Government for the purpose of conserving natural resources, improving the life standard of communities and alleviating poverty across rural areas in Tanzania. With an area of 771 km2, MBOMIPA is among the three WMA’s bordering Ruaha National Park in Iringa region with large number of animals. However, little has been documented on small mammalian carnivores (SMC) in the area. This study was therefore designed to assess communities’ knowledge and attitudes on trends and threats of SMC in the area. Structured questionnaires were used for collecting information from village game scouts, local tourist hunters (campsite attendants, hunters guide, drivers and tour guides). Eleven SMC species were reported in the current study, viz. Black backed jackal, Aardwolf, Bat eared Fox, Zorilla, Cape clawless otter, Striped weasel, African civet, Wild cat, Caracal, Honey badger, and Banded mongoose. Eighteen respondents reported an increase of SMC despite presence of many threats against their survival. Competition (20.8%) and fire (16.5%) were reported to be the leading factors threatening the SMC in the area. Information gathered from this study was considered important for wildlife managers when implementing conservation activities and future research on SMC

Evidence of Yersinia pestis DNA in rodents in plague outbreak foci in Mbulu and Karatu Districts, northern Tanzania

Tanzania journal of health research, 2013, Vol. 15, Issue 3Human plague remains a public health concern in Tanzania despite its quiescence in most foci for years, considering the recurrence nature of the disease. Appreciable researches have involved serological screening of rodents, fleas and humans but none has involved molecular detection and hence proving the presence of Yersinia pestis in rodents in the most recent affected foci, Mbulu and Karatu districts in northern Tanzania. The objective of the current study was to employ a simple PCR to detect Yersinia pestis plasminogen activator (pla) gene in various potential mammalian hosts/reservoirs. The study was conducted in five villages in Mbulu and one in Karatu districts during the period of no disease outbreak. Rodents and small wild carnivores were captured, anaesthetized, identified, sexed and autopsied. Liver, spleen, heart and lung specimens were collected and DNA extracted after which PCR was used to detect the Y. pestis pla gene. A total of 517 small mammals were captured; of which, 493 (95.4%) were from Mbulu and 24 (4.6%) from Karatu. Two Mastomys natalensis (one from each district) and one Gerbilliscus sp. in Mbulu district were positive for Y. pestis pla gene. In conclusion, our results have provided a proof on the presence of Y. pestis in the two rodent species (Mastomys natalensis and Gerbilliscus sp.) and thus providing indicative evidence that the two are potential reservoirs of the pathogen and hence may be responsible for maintaining the same during periods of no disease outbreaks

Evidence of Yersinia pestis DNA in rodents in plague outbreak foci in Mbulu and Karatu Districts, northern Tanzania

Tanzania journal of health research, 2013, Vol. 15, Issue 3Human plague remains a public health concern in Tanzania despite its quiescence in most foci for years, considering the recurrence nature of the disease. Appreciable researches have involved serological screening of rodents, fleas and humans but none has involved molecular detection and hence proving the presence of Yersinia pestis in rodents in the most recent affected foci, Mbulu and Karatu districts in northern Tanzania. The objective of the current study was to employ a simple PCR to detect Yersinia pestis plasminogen activator (pla) gene in various potential mammalian hosts/reservoirs. The study was conducted in five villages in Mbulu and one in Karatu districts during the period of no disease outbreak. Rodents and small wild carnivores were captured, anaesthetized, identified, sexed and autopsied. Liver, spleen, heart and lung specimens were collected and DNA extracted after which PCR was used to detect the Y. pestis pla gene. A total of 517 small mammals were captured; of which, 493 (95.4%) were from Mbulu and 24 (4.6%) from Karatu. Two Mastomys natalensis (one from each district) and one Gerbilliscus sp. in Mbulu district were positive for Y. pestis pla gene. In conclusion, our results have provided a proof on the presence of Y. pestis in the two rodent species (Mastomys natalensis and Gerbilliscus sp.) and thus providing indicative evidence that the two are potential reservoirs of the pathogen and hence may be responsible for maintaining the same during periods of no disease outbreaks

Evidence of Yersinia pestis DNA in rodents in plague outbreak foci in Mbulu and Karatu Districts, northern Tanzania

Human plague remains a public health concern in Tanzania despite its quiescence in most foci for years, considering the recurrence nature of the disease. Appreciable researches have involved serological screening of rodents, fleas and humans but none has involved molecular detection and hence proving the presence of Yersinia pestis in rodents in the most recent affected foci, Mbulu and Karatu districts in northern Tanzania. The objective of the current study was to employ a simple PCR to detect Yersinia pestis plasminogen activator (pla) gene in various potential mammalian hosts/reservoirs. The study was conducted in five villages in Mbulu and one in Karatu districts during the period of no disease outbreak. Rodents and small wild carnivores were captured, anaesthetized, identified, sexed and autopsied. Liver, spleen, heart and lung specimens were collected and DNA extracted after which PCR was used to detect the Y. pestis pla gene. A total of 517 small mammals were captured; of which, 493 (95.4%) were from Mbulu and 24 (4.6%) from Karatu. Two Mastomys natalensis (one from each district) and one Gerbilliscus sp. in Mbulu district were positive for Y. pestis pla gene. In conclusion, our results have provided a proof on the presence of Y. pestis in the two rodent species ( Mastomys natalensis and Gerbilliscus sp.) and thus providing indicative evidence that the two are potential reservoirs of the pathogen and hence may be responsible for maintaining the same during periods of no disease outbreaks

Factors associated with flea infestation among the different rodent species in Mbulu and Karatu districts, northern Tanzania

Flea infection with the bacterium, Yersinia pestis is acquired from reservoirs which include several rodents and other small mammals.  In areas that are endemic of plague, reservoirs of Y. pestis and various flea vectors are responsible for perpetuating existence of the disease.  The objective of this cross sectional study was to investigate the magnitude and factors associated with flea infestation among different rodent species of northern Tanzania, where outbreaks of plague have been recently reported. House rodents were trapped with box traps, while field and forest rodents were trapped with Sherman live traps. Fleas were removed from the rodents by using shoe-shining brush and were identified to genus level. Among the captured rodents, Rattus rattus (26.5%), Lophuromys flavopunctatus (16.5%), Praomys delectorum (16.2%) and Mastomys natalensis (32.3%) were most abundant rodent species, accounting for 91% of all species. Altogether, 805 fleas belonging to nine species were collected from 61% of the captured rodents. The most common fleas were Xenopsylla spp.; Dinopsyllus spp and Ctenophthalmus spp. Fleas were found to be highly abundant in M. natalensis, R. rattus, P. delectorum and L. flavopunctatus. Most of rodents were heavily infested with various flea species. These flea species probably play an important role in the transmission of plague in these two districts. We conclude that rodent species was the most important risk factor associating with flea infestation among the rodent population. Therefore, measures for control and prevention of plague in this area should particularly target rodents associated with high intensity of flea infestation

Plague in Tanzania: an overview

Human plague remains a public health concern in Tanzania despite its quiescence in most foci for years, considering the recurrence nature of the disease. Despite the long-standing history of this problem, there have not been recent reviews of the current knowledge on plague in Tanzania. This work aimed at providing a current overview of plague in Tanzania in terms of its introduction, potential reservoirs, possible causes of plague persistence and repeated outbreaks in the country. Plague is believed to have been introduced to Tanzania from the Middle East through Uganda with the first authentication in 1886. Xenopsylla brasiliensis , X. cheopis , Dinopsyllus lypusus , and Pulex irritans are among potential vectors while Lophuromys spp, Praomys delectorum , Graphiurus murinus , Lemniscomys striatus , Mastomys natalensis , and Rattus rattus may be the potential reservoirs. Plague persistence and repeated outbreaks in Tanzania are likely to be attributable to a complexity of factors including cultural, socio-economical, environmental and biological. Minimizing or preventing people’s proximity to rodents is probably the most effective means of preventing plague outbreaks in humans in the future. In conclusion, much has been done on plague diagnosis in Tanzania. However, in order to achieve new insights into the features of plague epidemiology in the country, and to reorganize an effective control strategy, we recommend broader studies that will include the ecology of the pathogen, vectors and potential hosts, identifying the reservoirs, dynamics of infection and landscape ecology