We investigated antibiotic resistance profiles of Escherichia coli among 960 samples obtained from chickens (236), humans (243), rodents (101) and soil (290). E. coli was isolated from 650 (67.7%) samples. Isolation frequency varied significantly between chickens, humans, rodents and soil samples, being 81.6%, 86.5%, 79.2% and 31.0%, respectively (p < 0.001). Resistance rates were particularly higher against imipenem (79.8%), cefotaxime (79.7%) and tetracycline (73.7%) and moderate against amoxicillin-clavulanate (49.4%). Overall, 78.8% of the isolates were multidrug-resistant (MDR) among which, 38.8%, 25.1%, 12.9% and 2.5% exhibited resistance to three, four, five and six different classes of antibiotics, respectively. Multidrug-resistant E. coli were observed in 27.7%, 30.3%, 10.8% and 10.0% of the isolates from chickens, humans, rodents and soil samples, respectively. Our results show high levels of antimicrobial resistance including MDR in E. coli isolated from chickens, humans, rodents and soil samples in Karatu, Northern Tanzania. Comprehensive interventions using a one-health approach are needed and should include improving (i) awareness of the community on judicious use of antimicrobial agents in humans and animals, (ii) house conditions and waste management and (iii) rodent control measures.

The interaction of rodents with humans and chicken in the household environment can facilitate transmission of multidrug-resistant (MDR) Escherichia coli (E. coli), causing infections that are difficult to treat. We investigated the presence of genes encoded for carbapenem, extended spectrum beta-lactamases (ESBL), tetracycline and quinolones resistance, and virulence among 50 MDR E. coli isolated from human (n = 14), chicken (n = 12), rodent (n = 10), and soil (n = 14) samples using multiplex polymerase chain reaction (PCR). Overall, the antimicrobial resistance genes (ARGs) detected were: blaTEM 23/50 (46%), blaCTX-M 13/50 (26%), tetA 23/50 (46%), tetB 7/50 (14%), qnrA 12/50 (24%), qnrB 4/50 (8%), blaOXA-48 6/50 (12%), and blaKPC 3/50 (6%), while blaIMP, blaVIM, and blaNDM-1 were not found. The virulence genes (VGs) found were: ompA 36/50 (72%), traT 13/50 (26%), east 9/50 (18%), bfp 5/50 (10%), eae 1/50 (2%), and stx-1 2/50 (4%), while hlyA and cnf genes were not detected. Resistance (blaTEM, blaCTX-M, blaSHV, tetA, tetB, and qnrA) and virulence (traT) genes were found in all sample sources while stx-1 and eae were only found in chicken and rodent isolates, respectively. Tetracycline resistance phenotypes correlated with genotypes tetA (r = 0.94), tetB (r = 0.90), blaKPC (r = 0.90; blaOXA-48 (r = 0.89), and qnrA (r = 0.96). ESBL resistance was correlated with genotypes blaKPC (r = 0.93), blaOXA-48 (r = 0.90), and qnrA (r = 0.96) resistance. Positive correlations were observed between resistance and virulence genes: qnrB and bfp (r = 0.63) also blaTEM, and traT (r = 0.51). Principal component analysis (PCA) indicated that tetA, tetB, blaTEM, blaCTX-M, qnrA, and qnrB genes contributed to tetracycline, cefotaxime, and quinolone resistance, respectively. While traT stx-1, bfp, ompA, east, and eae genes contributed to virulence of MDR E. coli isolates. The PCA ellipses show that isolates from rodents had more ARGs and virulence genes compared to those isolated from chicken, soil, and humans.

Globally, zoonoses have serious consequences due to their socioeconomic impacts. Ngorongoro District is home to a diverse range of wildlife and domestic animals, including rodents and dogs, which often coexist in close proximity with humans. The aim of the study was to identify the zoonotic bacteria present in wild rodents, domestic dogs, and humans using metagenomics next-generation sequencing technology. A cross-sectional study was conducted in 2022. This study used both Illumina and Oxford Nanopore sequencing technologies to identify bacteria in 530 blood samples collected from humans (n = 200), wild rodents (n = 230), and dogs (n = 100). Several zoonotic airborne/contagious bacteria, including Mycobacterium spp., Mycoplasma spp., Bordetella spp., and Legionella spp., were detected in wild rodents, domestic dogs, and humans. Arthropod-borne zoonotic bacteria such as Bartonella spp., Borrelia spp., and Rickettsia spp. were detected in all three hosts, while Orientia spp. was found in wild rodents and domestic dogs. Yersinia pestis, Streptobacillus spp. and Anaplasma spp. were found only in wild rodents. Other zoonotic bacteria found shared among wild rodents, domestic dogs, and humans are Leptospira spp., Brucella spp., and Salmonella spp. Generally, wild rodents had the highest prevalence of zoonotic bacterial species when compared to domestic dogs and humans. The detection of zoonotic bacteria in rodents, dogs, and humans supports the hypothesis that infections can spread between animals and humans sharing the same environment.

Climate change causes organisms, including species that act as parasite reservoirs and vectors, to shift their distribution to higher altitudes, affecting wildlife infestation patterns. We studied how ectoparasite distributions varied with altitude using two rodent species, Montemys delectorum and Rhabdomys dilectus, at different elevations (1500–3500 m). The ectoparasites infesting the two rodent species were influenced by the host sex, species, and temperature. We expected host density to predict parasite infestation patterns, because hosts in higher densities should have more parasites due to increased contact between individuals. However, temperature, not host density, affected ectoparasite distribution. Since temperatures decrease with elevation, parasite prevalences and abundances were lower at higher elevations, highlighting that the cold conditions at higher elevations limit reproduction and development—this shows that higher elevation zones are ideal for conservation. The rodents and ectoparasite species described in this study have been reported as vectors of diseases of medical and veterinary importance, necessitating precautions. Moreover, Mount Meru is a refuge for a number of endemic and threatened species on the IUCN Red List. Thus, the parasitic infection can also be an additional risk to these critical species as well as biodiversity in general. Therefore, our study lays the groundwork for future wildlife disease surveillance and biodiversity conservation management actions. The study found a previously uncharacterized mite species in the Mesostigmata group that was previously known to be a parasite of honeybees. Further investigations may shed light into the role of this mite species on Mount Meru.

In addition to their economic significance, rodents are hosts and transmit diseases. Most of rodent-borne diseases are endemic in rural Africa and sporadically lead to epidemics. Ngorongoro district is inhabited by humans, livestock, and wild animals. Therefore, a cross-sectional study was conducted to assess the level of knowledge, attitudes, and practices toward rodent-borne diseases among communities. The study used 3 focus groups, 20 key informant interviews, and the questionnaire (N=352) to collect data. The study found that 8.52% of respondents had good knowledge, 35.5% had a positive attitude and 94.3% had good practices toward rodent-borne diseases. The study revealed that only 28.13% of participants were aware of rodent-borne zoonoses. The majority of them (77.27%) believe that rodents are pests that destroy crops and do not transmit pathogens. Moreover, the results showed that the majority of them (82.9%) live in dilapidated huts that serve as rodent breeding places. Additionally, except for education and religion, the level of knowledge had no significant relationship with most of the participants’ demographic variables. When compared to individuals who didn’t attend school, those with secondary education (OR=7.96, CI=1.4-45.31, P=0.017) had greater knowledge of rodent-borne diseases and management. Similarly, to how attitude and practice were found to be considerably (r=0.3216, P=0.000) positively correlated, general knowledge and general practice scores were found to be significantly (r=0.1608, P=0.002) positively correlated. Despite showing good practices, the communities still lack knowledge of rodent-borne zoonosis. Rodent-borne disease education should be considered in Ngorongoro and other places.

Understanding species distribution across elevational gradients is crucial for developing conservation strategies for montane biotic systems. A survey of small mammals was conducted on Mount Meru at six elevations, ranging between 1500 m and 3650 m. A total of 803 small mammal individuals, including 2 shrew species and 13 rodent species, were documented. Of these, Crocidura newmarki and Lophuromys verhageni were endemic on Mount Meru. Species richness was highest at mid–elevations, which is in line with the global pattern for small mammals. Prior to our study, the most complete data on small mammals on Mount Meru was collected in 2009. Our study provides an opportunity to show how small mammal elevational distribution has changed, over the last decade. We found six species (Arvicanthis niloticus, Mastomys natalensis, Lemniscomys striatus, Dasymys incomtus, Cricetomys ansorgei, and Montemys delectorum), which were not documented in 2009, but did not find Otomys tropicalis. Interestingly, the community composition at higher elevations in 2021 resembles that at lower elevations in 2009, suggesting that small mammal species have moved their range upward over time. Climate change could be a factor associated with the distributional shift found.