Home ranges, sex ratio and recruitment of the multimammate rat (Mastomys natalensis) in semi-arid areas in Tanzania

Investigation of home ranges, sex ratio and recruitment of the multimammate rat (Mastomys natalensis) in semi-arid areas of Tanzania was conducted in maize and fallow fields using the capture-mark-release (CMR) technique. The aim of this study was to generate useful data for the management of M. natalensis. The relative home range size of M. natalensis was significantly higher during the wet [544 m2±25 standard error (SE)] than during the dry (447 m2 ±18 SE) season, in males (521 m2 ±23 SE) than in females (450 m2 ±17 SE) and in adults (576 m2 ±34 SE) than in juveniles (459 m2 ±16 SE). However, there were no significant differences between habitats. Sex ratio was not significantly different (p=0.44) between habitats. Recruitment was significantly higher (p=0.000) in maize fields (mean=0.43) than in fallow land (mean=0.32) and differed significantly over time (p=0.0001) with the highest recruitment recorded from April to July and the lowest from October to December. Management strategies should focus on managing rodents inhabiting maize fields using methods that affect their recruitment in order to reduce the population increase of M. natalensi

Identification of risk factors associated with transmission of plague disease in eastern Zambia

Am. J. Trop. Med. Hyg., 97(3), 2017, pp. 826–830Plague is a fatal, primarily rodent-flea-borne zoonotic disease caused by Yersinia pestis. The identificatio of risk factors of plague was investigated through questionnaire interview and conducting focus group discussion (FGD) in Sinda and Nyimba districts of eastern Zambia. A total of 104 questionnaires were administered to individual respondents and 20 groups consisting of 181 discussants, which comprised FGD team in this study. The study revealed that trapping, transportation, and preparation of rodents for food exposed the community to rodent and their fleas suggesting that plague may have occurred primarily by either flea bites or contact with infected wild rodents. The study also revealed that most people in communities consumed rodents as part of their regular diet; therefore, contact with small wild mammals was a common practice. The mode of transportation of freshly trapped rodents, in particular, carcasses risked human to flea bites. Questionnaire respondents (75%) and FGD discussants (55%) indicated that trappers preferred to carry rodent carcasses in small bags, whereas 55.8% and 20% respectively, reported hunters carrying carcasses in their pockets. Carrying of carcass skewers on trappers’ shoulders was reported by 38.4% and 20% of individual respondents and FGD, respectively. All these activities were exposing humans to rodents and their fleas, the natural reservoirs and vectors of (.2 plague, respectively. This study also showed that there is a statistically significant = 4.6878, P < 0.05), between digging of rodents from their burrows and the presence of fleas on the hunter’s bodies or clothes, which exposes humans to potentially flea bites in an enzootic cycle

Identification of risk factors associated with transmission of plague disease in eastern Zambia

Am. J. Trop. Med. Hyg., 97(3), 2017, pp. 826–830Plague is a fatal, primarily rodent-flea-borne zoonotic disease caused by Yersinia pestis. The identificatio of risk factors of plague was investigated through questionnaire interview and conducting focus group discussion (FGD) in Sinda and Nyimba districts of eastern Zambia. A total of 104 questionnaires were administered to individual respondents and 20 groups consisting of 181 discussants, which comprised FGD team in this study. The study revealed that trapping, transportation, and preparation of rodents for food exposed the community to rodent and their fleas suggesting that plague may have occurred primarily by either flea bites or contact with infected wild rodents. The study also revealed that most people in communities consumed rodents as part of their regular diet; therefore, contact with small wild mammals was a common practice. The mode of transportation of freshly trapped rodents, in particular, carcasses risked human to flea bites. Questionnaire respondents (75%) and FGD discussants (55%) indicated that trappers preferred to carry rodent carcasses in small bags, whereas 55.8% and 20% respectively, reported hunters carrying carcasses in their pockets. Carrying of carcass skewers on trappers’ shoulders was reported by 38.4% and 20% of individual respondents and FGD, respectively. All these activities were exposing humans to rodents and their fleas, the natural reservoirs and vectors of (.2 plague, respectively. This study also showed that there is a statistically significant = 4.6878, P < 0.05), between digging of rodents from their burrows and the presence of fleas on the hunter’s bodies or clothes, which exposes humans to potentially flea bites in an enzootic cycle

Challenges in determining the pathogenicity status of Leptospira isolates with phenotypic methods: The need for a polyvalent approach

African Journal of Microbiology Research, 2010; 4 (23): 2528-2533Understanding the pathogenic status of leptospires, the causative agents of leptospirosis, is important for successful laboratory diagnosis and control programmes of this zoonosis. Leptospires are difficult to differentiate morphologically; therefore, their pathogenic, intermediate or saprophytic status is currently determined based on both phenotypic tests like growth response in medium containing 8-azaguanine and growth at low temperature (13°C), and genotypic methods. The present study reports on the pathogenic versus saprophytic characterization of nine Leptospira isolates from animal hosts (rodents and dogs) and humans, with specific interest on a canine isolate coded “Dog109”, which showed an ambiguous or intermediate status according to conventional (phenotypic) and molecular (genotypic) tests. The results strongly indicate the need of a polyvalent analytical approach for improving the differentiation of the pathogenic status of circulating serovars

Ability of Cricetomys rats to detect Mycobacterium tuberculosis and discriminate it from other microorganisms

Tuberculosis 2011, vol 87:182 -186Trained African giant pouched rats (Cricetomys gambianus) have potential for diagnosis of tuberculosis (TB). These rats target volatile compounds of Mycobacterium tuberculosis (Mtb) that cause TB. Mtb and nontuberculous mycobacteria (NTM) species are related to Nocardia and Rhodococcus spp., which are also acid-fast bacilli and can be misdiagnosed as Mtb in smear microscopy. Diagnostic performance of C. gambianus on in vitro-cultured mycobacterial and related pulmonary microbes is unknown. This study reports on the response of TB detection rats to cultures of reference Mtb, clinical Mtb, NTM, Nocardia; Rhodococcus; Streptomyces; Bacillus; and yeasts. Trained rats significantly discriminated Mtb from other microbes (p < 0.008, Fisher’s exact test). Detection of Mtb cultures was age-related, with exponential and early stationary phase detected more frequently than early log phase and late stationary phase (p < 0.001, Fisher’s test) (sensitivity ¼ 83.33%, specificity ¼ 94.4%, accuracy ¼ 94%). The detection of naturally TB-infected sputum exceeded that of negative sputum mixed with Mtb, indicating that C. gambianus are conditioned to detect odours of TB-positive sputum better than spiked sputum. Although further studies on volatiles from detectable growth phases of Mtb are vital for identification of Mtb-specific volatiles detected by rats, our study underline the potential of C. gambianus for TB diagnosis

Challenges in determining the pathogenicity status of Leptospira isolates with phenotypic methods: The need for a polyvalent approach

African Journal of Microbiology Research, 2010; 4 (23): 2528-2533Understanding the pathogenic status of leptospires, the causative agents of leptospirosis, is important for successful laboratory diagnosis and control programmes of this zoonosis. Leptospires are difficult to differentiate morphologically; therefore, their pathogenic, intermediate or saprophytic status is currently determined based on both phenotypic tests like growth response in medium containing 8-azaguanine and growth at low temperature (13°C), and genotypic methods. The present study reports on the pathogenic versus saprophytic characterization of nine Leptospira isolates from animal hosts (rodents and dogs) and humans, with specific interest on a canine isolate coded “Dog109”, which showed an ambiguous or intermediate status according to conventional (phenotypic) and molecular (genotypic) tests. The results strongly indicate the need of a polyvalent analytical approach for improving the differentiation of the pathogenic status of circulating serovars

African pouched rats for the detection of pulmonary tuberculosis in sputum samples

The International Journal of Tuberculosis and Lung Disease, 2009; 13 (6):737–743SETTING: Resource-limited settings in sub-Saharan African countries. OBJECTIVE: To utilise African giant pouched rats (Cricetomys gambianus) for the diagnosis of tuberculosis (TB) in human sputum. DESIGN: A specially designed cage with 10 sniffi ng holes and cassette-carrier was used. The sputum samples were put in the sample cassette, containing 10 samples in line, placed under matching sniffi ng holes. Rats were trained to sniff each consecutive sample, and indicate TB positives by fi xing their nose for 5 seconds at the sniffi ng hole. This behaviour was maintained by food reinforcement upon correct indications. A total of 3416 samples were used. RESULTS: Of the 20 trained rats, 18 were able to discriminate positive from negative sputum samples, with average daily sensitivities ranging from 72% to 100%, and average daily false-positives ranging from 0.7% to 8.1%. The use of multiple rats signifi cantly increased sensitivity and negative predictive value. CONCLUSION: Utilising trained sniffer rats for TB detection is a potentially faster screening method and is at least as sensitive as smear microscopy. This method could therefore be suitable for active case fi nding, especially where large numbers of samples are to be analysed in resource-limited settings, to complement existing diagnostic techniques

Proportion of prevalence of <i>Leptospira</i> serovars in humans, animals and fish.

<p>Proportion of prevalence of <i>Leptospira</i> serovars in humans, animals and fish.</p