Zoonotic Dis., Volume 3, Issue 2 (June 2023) – 7 articles

We report a rare and interesting case of mixed infection with Leishmania infantum and Dirofilaria immitis associated with the incidental finding of microfilariae in the bone marrow of a 9-year-old, intact, male Bullmastiff which was seropositive to L. infantum. Clinical signs showed progressive weakness, pale mucosae membranes, and a very low body condition score. Laboratory abnormalities included moderate, normocytic, normochromic, non-regenerative anemia; mild leukocytosis, neutrophilia, monocytosis, and eosinopenia; low platelet count; elevated C reactive protein; mild hyperkalemia, hypoalbuminemia, and hyperbeta-2-globulinemia; and a low A/G ratio. Hypoadrenocorticism, euthyroid sick syndrome, and alteration in the fibrinolytic phase of hemostasis were also detected. Microfilariae were incidentally found in bone marrow cytology aspirate in the absence of clinical features indicative of co-infection with D. immitis. PCR confirmed the identification of the Dirofilaria species. It is assumed that the microfilariae may have left the microcirculation and migrated to bone marrow tissues by crossing the vessel wall. To the best of our knowledge, only one such case has been previously reported in dogs. Full article

Dogs live in close contact with humans as pets, for hunting, for security, and as a source of income. In addition, the meat is also consumed by some tribes in Nigeria. Dogs could therefore serve as reservoirs, carriers, and transmitters of zoonotic diseases. This review evaluates the literature from 2000 to 2020 for the prevalence and incidence of zoonotic pathogens associated with dogs in Nigeria. The results obtained show that overall, parasites constituted a majority (64%) of the zoonotic pathogens (or species) identified in dog hosts. A good number of studies have examined the role of ticks in the transmission of tick-borne pathogens. Further, bacteria make up 22% of the zoonotic pathogens. From this study, it appears that rabies is the major pathogen in dogs for which there is reliable evidence linking contact between humans and dogs. Oyo State in southwestern Nigeria and Plateau State in north-central Nigeria were the most frequently studied states, while prevalence/disease surveillance studies constituted 80% of the overall papers assessed. Interdisciplinary collaborations as well as research and diagnosis policy amendments are missing links to fully appreciate the role of dogs in the transmission of zoonotic diseases in Nigeria. Policies should integrate a one health approach in the Nigerian health system, whereby diagnostic screening of humans and animals by physicians and veterinarians includes zoonotic pathogens for more accurate diagnosis and control. Full article

Zoonotic and foodborne diseases are a major cause of morbidity and mortality, especially in low- and middle-income countries. Pork is a potential source of zoonotic and foodborne diseases, and pork consumption is rapidly increasing in Eastern and Southern Africa (ESA). Here, studies conducted in ESA describing pig- and pork-associated zoonotic and foodborne hazards were identified to clarify the distribution and prevalence of these hazards and identify research gaps in this region. A systematised literature review was conducted using MEDLINE and Web of Science to identify relevant articles according to pre-determined inclusion/exclusion criteria. In total, 140 articles from 14 countries were identified for review. A total of 42 hazards were identified, categorised as bacterial, viral, parasitic, arthropodal, or other, including drug residues. Among all identified hazards, Taenia spp. (n=40) was the most often studied, followed by Salmonella spp. (21), Escherichia coli (17), and Staphylococcus spp. (9). Further research is required to determine baseline data on the epidemiology and health and economic burden associated with pig- and pork-borne hazards and appropriate strategies are needed to mitigate the risk these hazards pose to communities. Full article

The objective of this study was to construct a recombinant adenovirus expressing the foot-and-mouth disease virus (FMDV) capsid protein of types O and A for future FMDV vaccines to be used in the livestock industry for the reduction in losses caused by FMD outbreaks. Three recombinant adenoviruses, rAdv-P12A3B3C-OZK93, rAdv-P12A3B3C-OA58, and rAdv-P12A3C-AF72, were packaged, characterized, and amplified using the AdMax^TM adenovirus packaging system, and the humoral and cellular immunity levels were further evaluated in guinea pigs with monovalent or bivalent forms. The results showed that the three recombinant adenoviruses could elicit high levels of humoral and cellular immune responses against FMDV types O and A when immunizing monovalent or bivalent forms, and the immune effect changes with the change in the proportion of recombinant adenovirus types O and A, laying an important foundation for the future development of a new FMD live-carrier vaccine. These results implied that the recombinant adenovirus expressing the FMDV capsid protein of types O and A could be used to prevent FMDV in livestock. Full article

Developing novel antiviral agents and approaches is essential for the treatment against human and zoonotic viruses. We had previously produced RNase P-based ribozyme variants capable of efficiently cleaving mRNA in vitro. Here, engineered ribozymes were constructed from an RNase P ribozyme variant to target the mRNA encoding human CC-chemokine receptor 5 (CCR5), an HIV co-receptor. The constructed ribozyme efficiently cleaved the CCR5 mRNA in vitro. In cells expressing the engineered ribozyme, CCR5 expression diminished by more than 90% and the infection of HIV (R5 strain Ba-L) decreased by 200-fold. The ribozyme-expressing cells resistant to R5 strain Ba-L still supported the infection of HIV X4 strain IIIB due to its use of CXCR4 instead of CCR5 as the co-receptor. Thus, the ribozyme is specific against CCR5 but not CXCR4. This indicates that RNase P ribozyme is effective and specific against CCR5 to diminish HIV infection, and also displays the viability of developing engineered RNase P ribozymes against human and zoonotic viruses. Full article

Zoonotic pathogens, an increasing threat to human health, typically originate in the wild but spill over to humans from domestic animals because of the high contact with them. Industrial farming involves an increased number of animals of a single species per given area. Such high stocking density facilitates pathogen transmission. This speeds evolution and also offsets the natural tendency of pathogens to trend toward mildness. On the other hand, close contact reduces transmission dependence on host mobility and thus could favor virulence. Forestalling this problem requires understanding opportunities for spillovers and evolution created by animal farming technologies and human-animal-ecosystem interactions. This manuscript considers two important risk factors of intensive animal farming, stoking density and homogeneity, to inform practices that could stop the next pandemic at its source. Full article