Zoonotic Diseases

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

Hepatitis E virus (HEV) is an emerging viral disease known to cause acute viral hepatitis globally. Various genotypes of HEV have been identified that produce genotype specific lesions depending on the HEV targeted population. Pregnant or immunosuppressed individuals develop significantly more severe hepatitis E in comparison to the general population. In the last 40 years, we discovered that the tropism of HEV is not restricted to the liver, and virus replication was demonstrated in multiple organs. Out of the 10 body systems described in humans, HEV produces lesions causing a broad range of extrahepatic clinical manifestations in each of them. Affected body systems include nervous and musculoskeletal, cardiovascular, digestive, endocrine, integumentary, renal, respiratory, immune, and reproductive systems producing systemic lesions. All extrahepatic signs are caused by either direct HEV replication in these tissues, or indirectly by various immune mediated mechanisms. Extrahepatic replication features of HEV allowed it to cross the placental barrier, blood–brain barrier (BBB), and blood–testis barrier (BTB) that do not typically grant entry to viruses in general. Thus, in this review, we summarized the extrahepatic replication sites of HEV, listed the body systems where HEV invaded, and described multiple animal models including immunocompetent and immunosuppressed that were used to study the extrahepatic replication sites of HEV. Full article

Schistosomiasis is one of the leading neglected tropical diseases in sub-Saharan Africa. Recorded case numbers of this chronic and debilitating helminth disease indicate Nigeria to be the most endemic country within this region. National control efforts have focused intensively on restricting human contact with freshwater sources of intermediate host snails. However, limited attention has been paid to the role of livestock as reservoir hosts and the prevalence of transmission of schistosomes to humans via farmed animals. The West African nations of Mali, Senegal, and the neighbouring Niger, Benin, and Cameroon have all reported the hybridization of the closely related species of Schistosoma haematobium, which infects humans, and S. bovis, which infects cattle. As these countries share the Niger and Benue rivers, with their tributaries, there is a distinct possibility of aquatic snails infected with hybrid schistosomes migrating to become established in the Nigerian river system. Here, we report on the current state of research in Nigeria that aims to elucidate key aspects of zoonotic schistosomiasis epidemiology. Factors promoting the hybridization of Schistosoma species are highlighted, and how available control measures can be optimized to address the emergence of schistosome hybrids is discussed. Full article

Coxiella burnetii (C. burnetii) can cause a serious human disease known as Q Fever (QF). Our study summarized seroprevalence data from occupational settings in Italy, a country characterized by low notification rates of QF (17 cases between 2015 and 2021). Through systematic research on 3 databases (PubMed, EMBASE, MedRxiv), all studies including seroprevalence rates of C. burnetii in Italy were retrieved, and their results summarized and compared. We identified a total of 7 articles for a total of 1178 workers, mostly from agricultural settings. A pooled seroprevalence of 44.0% (95% Confidence Interval [95%CI] 27.6 to 61.8) was calculated. Subgroup estimates ranged from 2.8% (95%CI 0.9–6.3) in forestry rangers to 49.2% (95%CI 26.8–72.0) in livestock farmers, and peaked at 73.7% (95%CI 56.9–86.6) and 75.9% (95%CI 13.4–98.5) in abattoir workers and veterinary professionals, respectively. Seroprevalence rates for C. burnetii largely exceeded the official notification rates, suggesting its substantial underreporting in Italy. Full article

Lyme disease is the most common vector-borne disease in the United States and Canada. The causative agent of Lyme disease in North America is the spirochete Borrelia burgdorferi. In western North America, the primary vector of Borrelia burgdorferi is the western black-legged tick, Ixodes pacificus. Surveillance and modelling efforts indicate that I. pacificus is primarily found in coastal California, Oregon, Washington and the southern coastal regions of British Columbia However, infection rates with B. burgdorferi among I. pacificus ticks remain low, ranging from 0.6% to 9.9%. Lyme disease case numbers in western North America are also relatively low compared to eastern North America. Enzootic maintenance of B. burgdorferi by hosts in natural environments and climatic factors may influence Lyme disease risk. The borreliacidal western fence lizard, Sceloporus occidentalis, may contribute to the low infection rates observed in I. pacificus ticks, while the migratory nature of avian hosts can allow for long-distance tick dispersal. Moderately warm and moist environments and protection from sunlight define the suitable habitats of I. pacificus ticks. In this review, we discuss the ecology and epidemiology of Lyme disease in relation to I. pacificus, as well as the need for more studies in western North America. Full article

Toxoplasma gondii is a zoonotic parasite globally infecting a wide range of species, including humans. Felids are the only known hosts that can excrete environmentally resistant oocysts into ecosystems. In boreal regions, Canada lynx (Lynx canadensis) are sought by hunters primarily for their fur, and they are occasionally eaten. We examined carcasses salvaged from trappers from boreal regions of eastern (n = 97) and western (n = 357) Canada. We detected T. gondii antibodies in fluid from thawed heart tissue using an enzyme-linked immunosorbent assay, DNA in brain and heart via magnetic capture and real-time PCR assay, and presence of DNA in feces using a real-time PCR with melt curve analysis. We detected antibodies against T. gondii and DNA in tissues in 24% and 19% of lynx, respectively. One lynx was positive for DNA of T. gondii in feces, which could indicate intestinal infection and potential for shedding oocysts. Our results indicate that lynx may be a useful sentinel species for monitoring environmental circulation of T. gondii in northern boreal regions and may pose a risk for transmission to other wildlife and to people handling or consuming lynx. Full article

Zoonotic diseases are a group of infectious diseases that are transmitted naturally from animals to humans. L. garvieae is a Gram-positive bacterium which is present in the aquaculture of freshwater and marine fish. Some isolated cases of infection have been described, considering it an opportunistic agent in immunosuppressed patients. The most recent appearance of severe infections in immunocompetent patients or colonizing cardiac prostheses has set off the alarms. This manuscript presents the first two patients with recurrent tonsillitis due to L. garvieae. A 15-year-old male and an 8-year-old male had recurrent tonsillitis with more than three episodes per year. A culture of tonsillar exudate in both cases showed growth of L. garvieae with an antibiogram showing multi-resistance to antibiotics. Given the parents’ wish not to carry out surgery, an autovaccine regimen with lysed bacteria was proposed with good evolution and remission of tonsillitis episodes in both cases. The oral autovaccine produces an immunomodulatory effect and could be a therapeutic weapon in the prevention of this zoonosis. Further studies are needed to determine the importance of foodborne transmission in human L. garvieae infections and to find suitable treatments for this wide range of infections. Full article

Zoonotic diseases occur as a result of human interactions with animals with the inadvertent transmission of pathogens from one to another. Zoonoses remain a major cause of morbidity and mortality among human populations, as they have been a source of pandemics in human history. Viral zoonoses account for a significant percentage of pathogens of zoonotic sources, posing a huge risk to men’s general health and fertility. This review identifies the existing knowledge on the effects of viral zoonotic diseases on male fertility. Evidence from reviewed articles showed that viral zoonotic diseases elicit an immune reaction that induces inflammatory mediators and impairs testicular functions such as spermatogenesis and steroidogenesis, leading to abnormal semen parameters that lead to subfertility/infertility. Although most zoonotic viruses linger in semen long after recovery, their presence in semen does not directly translate to sexual transmission. There is a need to further delineate the possible risk of the sexual transmission of these diseases. While a few of the viral zoonotic diseases discussed have been well-studied, there is a need to place attention on others so as to fully understand their effects on male reproduction and therefore take the right steps towards preserving male fertility. Full article

Anthrax is a highly fatal zoonotic disease that affects all species of livestock. The study aims to develop an early warning of epidemiological anthrax using machine learning (ML) models and to study the effect of El Niño and La Niña oscillation, as well as the climate–disease relationship concerning the spatial occurrence and outbreaks in Karnataka. The disease incidence data are divided based on El Niño and La Niña events from 2004–2019 and subjected to climate-disease modeling to understand the disease pattern over the years. Machine learning models were implemented using R statistical software version 3.1.3 with Livestock density, soil profile, and meteorological and remote sensing variables as risk factors associated with anthrax incidence. Model evaluation is performed using statistical indices, viz., Cohen’s kappa, receiver operating characteristic (ROC) curve, true skill statistics (TSS), etc. Models with good predictive power were combined to develop an average prediction model. The predicted results were mapped onto the Risk maps, and the Basic reproduction numbers (R₀) for the districts that are significantly clustered were calculated. Early warning or risk prediction developed with a layer of R₀ superimposed on a risk map helps in the preparedness for the disease occurrence, and precautionary measures before the spread of the disease. Full article

The red-rimmed melania or Malaysian Trumpet Snail, Melanoides tuberculata, is a common exotic freshwater snail that has been invading an increasing number of water bodies in North America. As a well-known host for trematodes causing human and animal diseases, the pattern of invasion and parasitic infection for this species is of great concern. Snail specimens were collected from an urban stream in Los Angeles that drains into a fragile, protected wetland ecosystem. Molecular analysis identified four trematode species: Haplorchis pumilio, Fasciola jacksoni, Parorchis sp. TH-2019, and an unclassified trematode species, Trematoda distomecercaria WN-2016. H. pumilio is responsible for haplorchiasis infections, previously considered endemic to Asia. F. jacksoni infection is a significant cause of mortality in Asian elephants. This study represents the first occurrence of F. jacksoni in North America and a novel occurrence of that trematode in association with M. tuberculata. This study also represents new occurrences of Parorchis sp. TH-2019 and an unclassified trematode species, Trematoda distomecercaria WN-2016, within California and North America. Parorchis sp. TH-2019 has previously only been documented in a marine whelk. This identification of these trematodes in association with M. tuberculata further exemplifies the need for ongoing monitoring and detection, especially considering the significance of H. pumilio and haplorchiasis to public health. Full article

The bacteria of the families Rickettsiaceae and Anaplasmataceae, harbored by arthropod vectors, may cause disease in animals and humans. The aim of this study was to screen ectoparasites collected from cats and dogs in Attica, Greece for the bacteria of the Rickettsiales group, by molecular methods. The ectoparasites examined were Ctenocephalides felis fleas and Rhipicephalus sanguineus s.l., Rhipicephalus sp., and Ixodes sp. ticks. Rickettsia felis was detected in 4.8% of C. felis fleas, and Rickettsia conorii was detected in 7.3% of R. sanguineus s.l. ticks. Ehrlichia canis was found in one R. sanguineus s.l. tick, and Wolbachia pipientis was detected in the majority of fleas. Another endosymbiont, Cancidatus Midichloria mitochondrii (Cancidatus Midichloriaceae), was detected in one Ixodes sp.. This is the first report of R. conorii and E. canis in R. sanguineus s.l. ticks in this study area. Given the fact that Greece is considered endemic for spotted fever group rickettsioses, further investigation of these rickettsial pathogens’ distribution in their vectors and hosts could enhance our knowledge of their epidemiology, in order to assess their potential implications for public health in this metropolitan area. Full article

Monkeypox (MPX) is a relatively unknown and minor resurgent viral zoonotic disease caused by the monkeypox virus (MPXV). The disease can spread from person to person or from animal to person. The disease is most prevalent in the tropical rainforests of West and Central Africa. The first MPXV outbreak was recorded in a monkey during 1958 as a small pox-like disease causing flu-like symptoms, such as chills and fever, as well as a rash, and the first MPXV case in a human was in a 9-month-old child in the Democratic Republic of the Congo on 1 September 1970. There were 16,016 laboratory confirmed cases of MPXV infection and five deaths reported in 75 countries/territories/areas across all six WHO Regions as of 22 July 2022. MPXV has a wide host range, including humans, squirrels, mice, rabbits, hamsters, porcupines, non-human primates (orangutans, chimps, sooty mangabeys, cynomolgus monkeys), black-tailed prairie dogs, African brush-tailed porcupines, rats, and shrews. MPXV replicates at the site of inoculation, the respiratory or oropharyngeal mucosa, and spreads to other organs, such as the skin, lungs, and gastrointestinal tract, where clinical signs and symptoms of the disease manifest. Before the rash appears, most patients have prominent lymphadenopathy, which distinguishes human MPX from small pox. This is followed by macules, papules, vesicles, pustules, umbilication, scabbing, and desquamation. Laboratory tools, such as virus isolation, PCR-based assays, haemagglutination inhibition assays, electron microscopy, ELISA, Western blotting, or immunohistochemistry, have been used to confirm diagnoses. Following a confirmatory diagnosis, tecovirimat, an FDA-approved antiviral drug, is currently available to treat severe cases of MPXV infection, along with symptomatic and supportive therapies. Physical and close contact activities, such as sleeping in the same room or on the same bed as the infected person, intimate contact with an infected partner, living in the same house as infected people, and sharing the same cups and plates, must be avoided to prevent the spread of the disease. Vaccination with vaccinia virus against monkeypox is approximately 85% effective and may protect against MPXV infection if administered within 4 days and up to 14 days (without showing any symptoms) after initial contact with a confirmed monkeypox case. Full article

The risk of acquiring hepatitis E virus (HEV) infections by wild animals living in the European wild nature has previously been reported and high anti-HEV antibody detection rates were detected in several animal species. However, data on the HEV seroprevalence of wild boars and deer held in game reserves are rare. In the present study, we investigated anti-HEV seroprevalence and HEV RNA in 38 deer and 15 wild boars living in a game reserve in Northern Germany. Surprisingly, none of the animals tested positive for HEV RNA in blood, liver, or muscle (diaphragm), and all animals (n = 53, 100%) were anti-HEV negative. In conclusion, HEV infections in enclosed areas, such as game reserves, in Germany are rare, and the risk of HEV transmission through meat from these animals to humans seems to be low. Full article