Seroepidemiological Survey of Rift Valley Fever Virus in Ruminants in Garissa, Kenya.

INTRODUCTION: Rift Valley fever (RVF) is a vector-borne zoonotic disease caused by phlebovirus in the family Bunyaviridae. In Kenya, major outbreaks occurred in 1997-1998 and 2006-2007 leading to human deaths, huge economic losses because of livestock morbidity, mortality, and restrictions on livestock trade. AIM: This study was conducted to determine RVF seroprevalence in cattle, sheep, and goats during an interepidemic period in Garissa County in Kenya. METHODS: In July 2013, we performed a cross-sectional survey and sampled 370 ruminants from eight RVF-prone areas of Garissa County. Rift Valley fever virus (RVFV) antibodies were detected using a multispecies competitive enzyme-linked immunosorbent assay. Mixed effect logistic regression models were used to determine the association between RVF seropositivity and species, sex, age, and location of the animals. RESULTS: A total of 271 goats, 87 sheep, and 12 cattle were sampled and the overall immunoglobulin G seroprevalence was 27.6% (95% CI [23-32.1]). Sheep, cattle, and goats had seroprevalences of 32.2% (95% CI [20.6-31]), 33.3% (95% CI [6.7-60]), and 25.8% (95% CI [22.4-42]), respectively. Seropositivity in males was 31.8% (95% CI [22.2-31.8]), whereas that of females was 27% (95% CI [18.1-45.6]). CONCLUSIONS: The high seroprevalence suggests RVFV circulation in domestic ruminants in Garissa and may be indicative of a subclinal infection. These findings provide evidence of RVF disease status that will assist decision-makers to flag areas of high risk of RVF outbreaks and prioritize the implementation of timely and cost-effective vaccination programs.

A systematic review of Rift Valley Fever epidemiology 1931-2014.

BACKGROUND: Rift Valley Fever (RVF) is a mosquito-borne viral zoonosis that was first isolated and characterized in 1931 in Kenya. RVF outbreaks have resulted in significant losses through human illness and deaths, high livestock abortions and deaths. This report provides an overview on epidemiology of RVF including ecology, molecular diversity spatiotemporal analysis, and predictive risk modeling. METHODOLOGY: Using the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines, we systematically searched for relevant RVF publications in repositories of the World Health Organization Library and Information Networks for Knowledge (WHOLIS), U.S Centers for Disease Control and Prevention (CDC), and Food and Agricultural Organization (FAO). Detailed searches were performed in Google Scholar, SpringerLink, and PubMed databases and included conference proceedings and books published from 1931 up to 31st January 2015. RESULTS AND DISCUSSION: A total of 84 studies were included in this review; majority (50%) reported on common human and animal risk factors that included consumption of animal products, contact with infected animals and residing in low altitude areas associated with favorable climatic and ecological conditions for vector emergence. A total of 14 (16%) of the publications described RVF progressive spatial and temporal distribution and the use of risk modeling for timely prediction of imminent outbreaks. Using distribution maps, we illustrated the gradual spread and geographical extent of disease; we also estimated the disease burden using aggregate human mortalities and cumulative outbreak periods for endemic regions. CONCLUSION: This review outlines common risk factors for RVF infections over wider geographical areas; it also emphasizes the role of spatial models in predicting RVF enzootics. It, therefore, explains RVF epidemiological status that may be used for design of targeted surveillance and control programs in endemic countries.

Bovine tuberculosis in Rwanda: Prevalence and economic impact evaluation by meat inspection at Société des Abattoirs de Nyabugogo-Nyabugogo Abattoir, Kigali.

Despite the significant public health burden of bovine tuberculosis (bTB) in Rwanda, the prevalence of bTB is poorly documented. This study was conducted to estimate the prevalence of bTB in cattle using gross examination of granulomatous lesions, to identify mycobacteria species in suspected samples, and to evaluate the economic impact of meat condemnation based on bTB-like lesions in the meat industry in Rwanda. Routine meat inspection was conducted at Société des Abattoirs de Nyabugogo (SABAN)-Nyabugogo Abattoir. Tissue samples including 31 lymph nodes, 3 lungs and 2 livers were obtained from cattle of different ages with gross tuberculous lesions. Mycobacterium bovis was identified using microscopy with Kinyoun staining and isolation of mycobacterial species in culture on Löwenstein-Jensen and Colestos media, further identified using biochemical tests. Our findings, based on culture and postmortem results, show that the prevalence of bTB is 0.5%(0.587*148/16753), with an overall gross tuberculous lesion prevalence of 0.9% (148/16753). The presence of lesions were higher in cattle aged 2 years and older (1.6% vs. 0.6%, p < 0.05) and higher in females than in males (1.4% vs. 0.6%, p < 0.05). Of the 36 samples tested, 26 (72.2%) were positive by microscopic examination with Kinyoun staining while M. bovis was culture-confirmed in 21 (58.7%) cases. Bovine tuberculosis caused condemnation of 1683.5 kg of meat, resulting in an estimated loss of $4810. Our findings indicate that the prevalence of bTB in Rwanda is significant, and that bTB is a major cause of meat condemnation requiring continued implementation of surveillance and control measures. Furthermore, the results from this study also show important variations in sensitivity of the different tests that were used to determine the prevalence of bTB in cattle in Rwanda.

Screening of some Kenyan medicinal plants for antibacterial activity.

Eleven medicinal plants used by traditional healers in Machakos and Kitui District were screened, namely: Ajuga remota Benth, Aloe secundiflora Engl, Amaranthus hybridus L, Cassia didymobotrya Fes, Croton macrostachyus Del, Entada leptostachya Harms, Erythrina abyssinica DC, Harrisonia abyssinica Oliv, Schkuhria pinnata O. Ktze, Terminalia kilimandscharica Engl and Ziziphus abyssinica Hochst for potential antibacterial activity against four medically important bacterial strains, namely: Bacillus cereus ATCC 11778, Escherichia coli ATCC 25922, Micrococcus lutea ATCC 9341 and Pseudomonas aeruginosa ATCC 27853. The antibacterial activity of methanol extracts was determined as the minimum inhibitory concentration (MIC). The plant extracts were more active against Gram-positive (G+) than Gram-negative (G-) bacteria. The positive controls were streptomycin and benzylpenicillin for G- and G+ bacteria, respectively, both had a significant MIC at <1 mg/mL. The most susceptible bacteria were B. cereus, followed by M. lutea, while the most resistant bacteria were Ps. aeruginosa, followed by E. coli. The present study supports the use of these plants by the herbalists in the management of bacterial ailments. H. abyssinica and T. kilimandscharica showed the best antibacterial activity; hence these plants can be further subjected to phytochemical and pharmacological evaluation.

A survey of bovine cysticercosis/human taeniosis in Northern Turkana District, Kenya.

Bovine cysticercosis is a zoonosis that is mainly of socioeconomic and public health importance. A survey of this disease was carried out in Northern Turkana District, Kenya to estimate the prevalence through both serology and meat inspection, to determine the prevalence of the adult tapeworm in the human definitive host, and to determine risk factors for cattle seropositivity. This information is of public health importance and will be of use in assessing economic losses due to downgrading, refrigeration or condemnation of infested carcasses. The study area was stratified into the three livestock grazing regions of Oropoi to the south, Lokichoggio-Mogilla centrally and Kibish in the north for the purposes of the serological and questionnaire (n = 53 herd owners) data. Five adakaars (grazing units) were selected and 34, 63, 49, 75 and 571 cattle serum samples obtained from these. The slaughter slabs of Lokichoggio and Kakuma were visited and 188 serum samples were obtained from slaughter cattle and compared to results of meat inspection. Human stool samples were collected in each of the three grazing areas and 66, 97 and 78 samples were obtained. The seroprevalence of cysticercosis in cattle was estimated at 16.7% (95% CI 13-20.9%) using a secretory-excretory antigen detection ELISA. There was poor agreement between meat inspection and serology (k = 0.025; p = 0.2797). The prevalence of taeniosis was estimated as 2.5% (95% CI 0.8-5.6%) by microscopy. A backwards elimination logistic regression analysis indicated that the grazing unit (Adakaar), the deworming history of household members and the distance (>2 km) of grazing fields from the homestead were significant explanatory variables for cattle being found to be positive on serology. An intra-cluster correlation coefficient (ICC) of 0.07 (0.02-0.12); p < 0.0001 was calculated for bovine cysticercosis in this area.

Antibacterial and cytotoxic activity of Kenyan medicinal plants.

Seven medicinal plant extracts traditionally used in Kenya, mainly for management of infectious conditions, were chosen and screened for their antibacterial activity against Gram-negative (Pseudomonas aeruginosa and Escherichia coli) and Gram-positive (Bacillus cereus and Staphylococcus aureus) bacteria. Antibacterial activity was tested using the broth dilution method. Harrisonia abyssinica and Terminalia kilimandscharica extracts showed significant activity against Gram+ and Gram- bacteria. The methanolic extracts of T. kilimandscharica bark and H. abyssinica bark and leaves showed minimum inhibitory activity against all tested bacteria, with minimal inhibitory concentrations ranging from 25-150 mg/mL. Ajuga remota and Amaranthus hybridus, which are lethal to brine shrimp nauplii, showed significantly lower antibacterial activity than those that were relatively non-toxic.

Antibacterial and cytotoxic activity of Kenyan medicinal plants

Seven medicinal plant extracts traditionally used in Kenya, mainly for management of infectious conditions, were chosen and screened for their antibacterial activity against Gram-negative (Pseudomonas aeruginosa and Escherichia coli) and Gram-positive (Bacillus cereus and Staphylococcus aureus) bacteria. Antibacterial activity was tested using the broth dilution method. Harrisonia abyssinica and Terminalia kilimandscharica extracts showed significant activity against Gram+ and Gram- bacteria. The methanolic extracts of T. kilimandscharica bark and H. abyssinica bark and leaves showed minimum inhibitory activity against all tested bacteria, with minimal inhibitory concentrations ranging from 25-150 mg/mL. Ajuga remota and Amaranthus hybridus, which are lethal to brine shrimp nauplii, showed significantly lower antibacterial activity than those that were relatively non-toxic.

Ethnopharmacological survey of Samburu district, Kenya.

BACKGROUND: Ethnobotanical pharmacopoeia is confidently used in disease intervention and there is need for documentation and preservation of traditional medical knowledge to bolster the discovery of novel drugs. The objective of the present study was to document the indigenous medicinal plant utilization, management and their extinction threats in Samburu District, Kenya. METHODS: Field research was conducted in six divisions of Samburu District in Kenya. We randomly sampled 100 consented interviewees stratified by age, gender, occupation and level of education. We collected plant use data through semi-structured questionnaires; transect walks, oral interviews and focus groups discussions. Voucher specimens of all cited botanic species were collected and deposited at University of Nairobi's botany herbarium. RESULTS: Data on plant use from the informants yielded 990 citations on 56 medicinal plant species, which are used to treat 54 different animal and human diseases including; malaria, digestive disorders, respiratory syndromes and ectoparasites. CONCLUSION: The ethnomedicinal use of plant species was documented in the study area for treatment of both human and veterinary diseases. The local population has high ethnobotanical knowledge and has adopted sound management conservation practices. The major threatening factors reported were anthropogenic and natural. Ethnomedical documentation and sustainable plant utilization can support drug discovery efforts in developing countries.