Zoonotic Diseases

The One Health approach integrates human, animal, and environmental health to address complex challenges like emerging zoonotic diseases and antimicrobial resistance (AMR). Singapore’s dense urban environment, biodiversity, and role as a global hub make it vulnerable to these health threats, necessitating a robust and coordinated One Health framework. This paper reviews Singapore’s One Health strategy, focusing on governance, surveillance, cross-sector partnerships, and public health infrastructure. A structured literature review, including peer-reviewed articles and grey literature, identified key strengths and gaps. Strengths include interagency coordination through the One Health Coordinating Committee, advanced surveillance systems like CDLENS and SIDPIC, and key institutions such as the National Centre for Infectious Diseases (NCID) and the National Public Health Laboratory (NPHL). However, gaps remain in multi-sector engagement, data-sharing mechanisms, and public awareness of One Health principles. To address these challenges, this paper recommends enhancing multi-sector collaboration, strengthening data-sharing networks, and increasing public education on One Health. Investments in preventive medicine, cross-border capacity-building, and leveraging artificial intelligence for predictive analytics are essential for bolstering Singapore’s health security. By addressing these gaps, Singapore can enhance its preparedness and serve as a global leader in One Health implementation. Full article

The coronavirus disease 2019 (COVID-19) pandemic caused great damage not only in terms of morbidity and mortality, but also intense social, economic, institutional and political disruptions, and costs that upended and challenged assumptions about our preparedness to deal with such global infectious disease threats [...] Full article

Bats and rodents serve as reservoirs for numerous zoonotic pathogens, including species of Trypanosoma and Leishmania. Domestic rats host the flea-transmitted Trypanosoma (Herpetosoma) lewisi, which can be associated with humans, particularly young or immunocompromised individuals. Using Fluorescent Fragment Length Barcoding (FFLB) and phylogenetic analyses based on SSU rRNA sequences, we identified two Herpetosoma species, T. lewisi-like and T. musculi-like species, in bats of different families inhabiting rooftops and peridomestic structures in Brazil (44%, 107 bats examined) and Venezuela (50%, 52 bats examined). These species are typically associated with Rattus spp. (domestic rats) and Mus musculus (house mice), respectively. Furthermore, bats were co-infected with up to five other species, including Trypanosoma dionisii, Trypanosoma cruzi marinkellei, and isolates from the Trypanosoma Neobat clade, all strongly associated with bats, and Trypanosoma cruzi and Trypanosoma rangeli, known to infect various mammals, including humans. Therefore, our findings expand the known host range of Herpetosoma to bats, marking the first report of potential spillover of Herpetosoma trypanosomes from rodents to bats and underscoring the potential for the cross-species transmission of flea-borne trypanosomes. These results highlight the need for a One Health approach to assess infection risks associated with trypanosome spillover from synanthropic rodents and bats to humans. Full article

Highly pathogenic avian influenza (HPAI) surveillance for influenza A virus (IAV) in the United States is conducted using a National Animal Health Laboratory Network (NAHLN) real-time reverse transcriptase–polymerase chain reaction (rRT-PCR). Samples showing the presence of IAV are confirmed and characterized at the national reference laboratory. During the H5N1 HPAI outbreak in 2022, our laboratory reported the detection of IAV in a PA commercial chicken flock using rRT-PCR targeting the matrix gene, which was negative for the H5/H7 subtypes. IAV was not detected by additional sampling of the birds the following day with rRT-PCR. The virus detected was characterized as a human seasonal H3N2 with whole-genome sequencing (WGS). Further investigation revealed that the collector who visited the farm was diagnosed with an IAV infection. This case report emphasizes the importance of farm biosafety and biosecurity, of conducting regular reviews of worker safety protocols, and of advanced molecular techniques like WGS for viral characterization and epidemiology. Full article

Halicephalobus gingivalis (H. gingivalis) is a very rare opportunistic cause of fatal meningoencephalomyelitis in equids but may also cause parasitic infections in exposed humans via zoonotic transmission (from animals to humans). We herein report a 39-year-old veterinarian who was exposed to aspirated gastric contents while inserting a nasogastric tube into a horse with signs of uveitis. This procedure requires application of oral suction to the end of the tube to ensure correct placement. Histopathology of the horse’s enucleated eye later revealed H. gingivalis infection, and the horse developed acute kidney injury, ataxia, and other signs of neurological disease. The horse later progressed to death despite supportive care and administration of the broad-spectrum antiparasitic, ivermectin. Two months later, the veterinarian received prophylactic ivermectin consisting of two 200-mcg/kg doses. The patient reported feeling well and was without any systemic or focal signs or symptoms prior to this prophylactic treatment and continued feeling well when followed up at 4 months post exposure. Blood work was unremarkable, with no eosinophilia (eosinophils 0.1 × 10⁹/L, normal <0.4 × 10⁹/L). Meticulous hand hygiene and alternatives to unprotected oral suction should be considered in veterinary medicine as the potentially increasing risk of occupational exposure to zoonotic helminthiases makes this a public health concern. Full article

Background: Environmental changes impact bat–human interactions, heightening concerns of pathogen spillover and highlighting the need to understand human–bat interactions in the context of ecosystems. The objective of this study was to assess factors associated with human contact with bats in communities living near bat roosts in Northern Tanzania. Methods: A cross-sectional survey was used to investigate the factors associated with human contact with bats. Utilizing a standardized questionnaire administered through face-to-face interviews, relevant data were collected from respondents living in or near regions characterized by high bat density. Descriptive analyses followed by bivariate and multivariate analyses were performed to assess the association between the investigated factors and the outcome variable of interest, contact with bats. Results: Data were collected from 325 respondents. Of the respondents, 57.5% (187/325) reported bat contact, and only 4% believed bats can transmit rabies. The following factors were significantly associated with human–bat contact: being unaware that bats can transmit diseases like rabies (AOR = 8.63, CI = 1.04, 71.43, p = 0.045), feeling safe to handle bats with bare hands (AOR = 3.47, CI = 1.71, 7.05, p < 0.001), not washing hands thoroughly after bat bite or scratch (AOR = 2.43, CI = 1.29, 4.59, p = 0.006), using water from ponds, rivers or wells (AOR = 5.58, CI = 3.17, 9.79, p <0.001), age > 45 years (AOR = 1.77, CI = 1.0, 3.14, p = 0.047) and a low level of education (AOR = 5.86, CI = 2.97, 11.57, p <0.001). Conclusion: The study findings highlight the key factors to be targeted when developing strategies aimed at improving the community’s knowledge of the potential risks of zoonotic infectious diseases associated with bats and reducing the likelihood of human–bat contact and the related public health risks in communities living near bat roosting sites in Tanzania. Full article

Ticks are obligate hematophagous ectoparasites notorious for their role as vectors of pathogens that affect humans and animals, particularly relative to the propagation of emerging infectious diseases (EIDs). Two important factors facilitating the role of ticks in the propagation of EIDs are their potential for the development of resistance to acaricides and the expansion of nonindigenous tick species into new geographic regions. The acquisition of acaricide resistance enables tick populations to be less susceptible to vector control programs. Expansion of the geographic distribution of tick populations increases the likelihood of access to new host species as well as new pathogens. Understanding of the microbiome of ticks continues to evolve, providing critical insights into tick biology. The tick microbiome largely comprises endosymbionts, pathogenic organisms, and commensal bacteria. Endosymbionts are highly preserved and vertically transmitted in ticks from mother to offspring, and their role in the survival of ticks is well recognized. Similarly, the role of ticks as vectors of pathogens is well established. However, commensal bacteria in ticks are acquired from the environment and while ingesting a blood meal. Because many tick species spend most of their lifetime off the hosts, it can be assumed that the richness and diversity of commensal bacteria are highly variable and dependent on the ecosystem in which the tick exists. This mini-review identifies some of the critical data gaps relevant to the role of and influence of commensal bacteria on the vectorial capacity of ticks. As ticks move into new habitats, are locally acquired commensal bacteria playing a role in adaptation to the new habitat? Apart from the conventionally understood mechanisms of acaricide resistance in ticks, are the commensal bacteria influencing the development of acaricide resistance at the population level? Full article

SARS-CoV-2 rapidly mutated, causing different waves of outbreaks worldwide. Bhutan experienced three major outbreaks of COVID-19 before experiencing the outbreak driven by the Omicron variant in January 2022. The data collected by the National Outbreak Investigation and Surveillance Team during the Delta variant-driven outbreak and Omicron outbreak were accessed and analyzed. The data were analyzed using R statistical software. Descriptive analysis was carried out for the entire dataset and the statistical comparison between the two outbreaks was carried out using student’s t-test and Pearson’s chi-square test. During the Delta variant-driven outbreak, a total of 1648 cases were reported, with a daily average of 13 cases. The highest one-day case number reported was 99. On the contrary, within 33 days, a total of 3788 cases were reported with a daily average of 115 cases during the Omicron outbreak. The highest one-day case number reported was 312. The median incubation period was 3 days (range = 0–18 days) and 1 day (range = 0–14 days) during the Delta and Omicron-driven outbreaks, respectively. The number of symptomatic cases was significantly higher during the Delta outbreak (p-value < 0.0001). Of the total cases reported during the Delta outbreak, 1175 (71.3%) had received a single dose of the vaccine, 79 (5%) received two doses, while 394 (24%) were unvaccinated. During the Omicron outbreak, 1957 (52%) cases had received their booster (third dose), 904 (23.8%) received two doses and only 40 (1%) received a single dose of the vaccine. The number of unvaccinated cases was 887 (23.4%), of which 375 (10%) were children below 12 years. Our findings corroborate the enhanced transmissibility of the Omicron variant as reported elsewhere. We report significantly less symptomatic cases during the Omicron outbreak. Further, our data show that the incubation period for the Omicron variant is shorter compared to the Delta variant (p-value < 0.0001). Full article

The aim of this study was to characterize the antimicrobial resistance phenotype and genotype of non-typhoidal Salmonella spp. isolated in Luanda, Angola. Between 2013 and 2015, human clinical samples, food, and environmental samples (n = 290) were collected at different regions of Luanda city and screened for the presence of Salmonella spp. Bacterial isolates were preliminarily identified using the API 20E Kit, and their identification was confirmed using PCR and serotyping. All Salmonella spp. isolates were tested by minimum inhibitory concentration against 19 antimicrobials. The isolates were also screened using PCR for the presence of resistance genes (bla_OXA-1, bla_SHV, bla_TEM, sul1, sul2, sul3, qnrA, qnrB, qnrS, qnrC, qnrD, aac(6′)-Ib, dfrIa [targeting dfrA1, dfrA5, dfrA15, dfrA15b, dfrA16, dfrA16b] and dfrA12, cmlA, and floR) and typed using pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). Salmonella enterica non-typhoidal was detected in 21.3% of the clinical samples (n = 32/150), 11.1% of the food samples (n = 10/90), and 26% of the environmental samples (n = 13/50). Serotyping revealed that the monophasic variant of Salmonella Typhimurium (Salmonella enterica serovar 4,[5],12:i:-) was detected in 38.1% of the samples. Moreover, serovar Salmonella Enteritidis was the second most frequent. Only 7.3% of the isolates were resistant to at least one antimicrobial. Furthermore, isolates from different origins (clinical, environmental, and food) were associated with the same lineages, Salmonella Enteritidis ST11 and S. enterica ser. Typhimurium ST313. The detection of S. enterica serovar 4,[5],12:i:- in different settings reinforces the need for a One Health approach to control this zoonosis in Angola. Full article

A comparative medicine approach, whereby similarities and differences in biology between human and veterinary species are used to enhance understanding for the benefit of both, is highly relevant to the development of viral vaccines. Human and equine influenza share many similarities in pathogenesis and immune responses. The DNA vaccine approach offers potential advantages for responding rapidly and effectively to outbreaks or pandemics in both humans and animals, especially in under-resourced regions. The European and American vaccine regulatory authorities require demonstration of vaccine efficacy in animal models. However, mice, the most widely used model, are not naturally infected with influenza viruses, resulting in different pathobiology. Additionally, mice as a model for DNA vaccine testing appear to overestimate the humoral immune response compared to other mammalian species. In this review, we propose that testing of DNA vaccines against influenza type A viruses (and other shared pathogens) in the horse can provide valuable knowledge for the development of human DNA vaccines. Full article

Some Corynebacterium strains produce toxins that are similar to those produced by Corynebacterium diphtheriae, leading to human infections that are often transmitted through zoonotic diseases. A novel species, which is formerly classified as Corynebacterium ulcerans lineage II, was recently re-evaluated and renamed “Corynebacterium ramonii sp. nov.”. We isolated C. ramonii from a human skin ulcer in Japan in 2023 (KCU0303-001) and identified it as ST344 using a genomic analysis. In addition, C. ramonii KPHES-18084 (ST344) and six strains of C. ulcerans (ST337/ST1011) were isolated from the oral cavities of 7/208 rescued cats (3.4%). The human ulcer strain KCU0303-001 and the rescued cat strain KPHES-18084 were found to be ST344 and closely related clones by core-genome and pan-genome analyses, suggesting that ST344 may be endemic to both clinical and companion animals in Japan. In support of this finding, another clinical isolate of ST344 (TSU-28 strain) was reported in Japan in 2019. Although ST337 is the most common C. ulcerans infection, the second most recent clinical isolate of C. ramonii, ST344, might be increasing; therefore, further genomic surveillance is required to monitor C. ramonii and C. ulcerans infections. Full article

National parks provide visitors access to hiking, camping, and the outdoors. These activities are associated with an increased risk of tick exposure. This brief report is observational, depicting case reports using raw data, and is not intended to analyze or establish risk but rather to examine geographic areas for potential future research and to identify disparities between canine and human disease reports within the same location. Locally vs. travel-acquired data are not provided by most public health departments in the U.S. Therefore, multimodal data analyses are needed for an improved understanding of disease risk. With data limitations in mind, observations from human and canine comparisons, in addition to tick presence, in this report include (1) tick-borne diseases are reported at most national park areas in the U.S., with the highest case reports in park areas located in Maine and Minnesota; (2) the average total tick-borne diseases combined (i.e., Lyme disease, ehrlichiosis, and anaplasmosis) for park areas allowing dogs is 15.34%. In comparison, the average for national parks without dogs is 8.7%, indicating the need for further study to assess human activity with pets, considering geography and ecology as potential explanatory factors; (3) canine data do not align with human data in many national park geographic areas; and (4) Ixodes scapularis presence overlaps with human and canine disease. Using multimodal data can assist with assessing risk when travel vs. local acquisition is unknown. Full article

Chikungunya and dengue are arboviral diseases transmitted by mosquitoes that have been increasingly recognized as public health concerns in Sub-Saharan Africa. Several studies conducted in Nigeria and other West African countries have revealed the seroprevalence burden and cocirculation of antibodies against mosquito-borne infections, thereby revealing a significant burden and clinical outcome complexities that have largely gone undetected. The current research study has important implications for disease surveillance, prevention strategies, and healthcare planning in Nigeria and other Sub-Saharan countries. A cross-sectional study was conducted on 871 outpatients and pregnant women from three regions of Nigeria. CHIKV and DENV immunoblot molecular diagnostic assays were used to analyze the serum samples for the presence of arboviral antibody serological markers IgG (Mikrogen Diagnostik, Germany) with DENV nonstructural protein 1 and DENV Equad and CHIKV virus-like particles (VLPs), according to the manufacturer’s instructions. A total of 871 participants were recruited from three geographical regions in Nigeria. Among them, 17.5% (152/871) were from Abia (southern Nigeria), 34.4% (300/871) were from Kaduna (northern Nigeria), and 48.1% (419/871) were from Nasarawa (central Nigeria). The ages of the participants ranged from 0 months to 80 years, with a mean age of 36.6 years. Of the 871 subjects, 71.0% (619/871) were female, and 29.0% (252/871) were male. The overall cohort detectable antibody seropositivity against CHIKV was 64.9% (565/871), 95% CI (61.74–68.06); DENV, 44.7% (389/871), 95% CI (41.41–47.99); and CHIKV-DENV cocirculation antibodies, 31.6% (95% CI 29–35). This study highlighted the unpredictably high seroprevalence, expansion, magnitude, and undetected burden of chikungunya and dengue in Nigeria. Full article

Prion diseases, also called transmissible spongiform encephalopathies (TSEs), are fatal neurodegenerative diseases characterised by the accumulation of an abnormal prion protein isoform (PrP^Sc: rich in β-sheets—about 30% α-helix and 43% β-sheet), which is converted from the normal prion protein (PrP^C: predominantly α-helical—about 42% α-helix and 3% β-sheet). However, prion disease has not been reported in horses up to now; therefore, horses are known to be a species resistant to prion diseases. Residue S167 in horses has been cited as a critical protective residue for encoding PrP conformational stability in prion-resistance. According to the “protein-only” hypothesis, PrP^Sc is responsible for both the spongiform degeneration of the brain and disease transmissibility. Thus, understanding the conformational dynamics of PrP^Sc from PrP^C is key to developing effective therapies. This article focuses on molecular dynamics and optimization studies on the horse PrP wild type and its S167D mutant, respectively, to understand their conformational dynamics and optimized confirmation; the interesting results will be discussed. Full article

Escherichia coli in untreated milk leads to economic losses from subclinical mastitis and reduced milk production, while also posing a public health risk due to the emergence of antimicrobial resistant strains, particularly associated with consuming unpasteurized milk and dairy products. This study aimed to determine the prevalence and antimicrobial resistance (AMR) of E. coli isolated from buffalo milk in Siddarthanagar Municipality of Rupandehi district, Nepal. A total of 102 milk samples were collected from lactating buffaloes. The isolation and identification of E. coli were carried out using enrichment media, selective media, and biochemical tests. Antimicrobial susceptibility testing was carried out using the Kirby–Bauer disk diffusion method on Mueller–Hinton agar (Merck), according to the Clinical and Laboratory Standards Institute (CLSI) recommendations. Resistance was tested against gentamicin, amikacin, ciprofloxacin, enrofloxacin, ceftriaxone, ceftazidime, cotrimoxazole, and chloramphenicol. In addition to this, farmers were administered a questionnaire consisting of both open- and close-ended questions to identify various animal-related and management-related risk factors associated with the prevalence of E. coli. The prevalence of E. coli in our study was 29.4% (n = 30/102). Ceftriaxone and ceftazidime showed 100% resistance, while cotrimoxazole and amikacin showed 86.7% and 80% resistance, respectively. Furthermore, 86.7% of E. coli isolates were multidrug resistant (MDR). Despite suggestive trends, associations between E. coli prevalence and risk factors lacked statistical significance, necessitating further research. While some antibiotics exhibited effectiveness, many faced resistance, highlighting the need for prudent antimicrobial usage and increased awareness among farmers. Raising awareness about milk pasteurization and implementing food safety practices is essential for ensuring farmers and public health. Full article

Emerging zoonotic diseases are one of the main threats to human and animal health. Among the agents with the potential for zoonoses, those of bacterial origin have great relevance in Public Health. Rodents are considered one of the main reservoirs of pathogens that represent a risk to human health or animal species. We used massive 16S ribosomal RNA gene amplicon sequencing to survey bacteria present in the spleen of six species of rodents in Panama in order to identify bacterial taxa with zoonotic potential in the country. We found 3352 bacterial Amplicon Sequence Variants (ASVs, i.e., phylogenetic species) in the spleen of six rodent species surveyed (Liomys adspersus, Melanomys caliginosus, Mus musculus, Proechimys semispinosus, Rattus rattus, Zygodontomys brevicauda). This bacterial community was represented by 25 phyla, 55 classes, 140 orders, 268 families, and 508 genera. The three predominant phyla were Actinobacteria, Firmicutes, and Proteobacteria, and the five predominant classes were Actinobacteria, Alpha- and Gammaproteobacteria, Bacilli, and Clostridia. There were seven high-abundance genera: Acinetobacter, Bartonella, Cutibacterium, Enterococcus, Sarcina, Staphylococcus, and Wolbachia. Genera found with less abundance included Bradyrhizobium, Chryseobacterium, Clostridium, Corynebacterium, Lactobacillus, Pseudonocardia, Rhodococcus, and Sphingomonas. Some of these genera (high or low abundance) have clinical importance. The identification of bacterial taxa with zoonotic potential in rodent species performed here allows us to have surveillance mechanisms for these pathogens and to be able to recognize localities to be prioritized for prevention of transmission and outbreaks, thus being of value for public health in Panama. Full article

Bat coronaviruses cause a wide range of illnesses in humans and animals. Bats are known to harbor a wide diversity of Alphacoronaviruses and Betacoronaviruses. Betacoronaviruses have been linked to Severe Acute Respiratory Syndrome (SARS), Middle East Respiratory Syndrome (MERS), and other diseases such as gastroenteritis, bronchiolitis, and pneumonia. In the last 20 years, three betacoronaviruses emerged and caused widespread outbreaks in humans, including two deadly betacoronavirus epidemics, SARS-CoV, with mortality rate of 10%, and MERS-CoV, with mortality rate of 34.7%, and SARS-CoV-2, which caused the COVID-19 pandemic, with mortality rate of 3.4%. Studies have shown that bats are the main natural reservoirs for these viruses or their ancestral viruses. Observed variations in bat coronavirus genomes indicate that these viruses may have a potential to transmit to other hosts in close contact with humans and subsequently transmit to humans. As of today, there are no reported cases of direct coronavirus transmission from bats to humans. One reason for this might be that intermediate hosts are required for the transmission of bat coronaviruses to humans. Further studies are needed to map the amino acids and genomic regions responsible for the interactions between the spike of coronavirus and its receptors. Full article

Background: Taeniosis and cysticercosis are human infections caused by the pork tapeworm, Taenia solium. This study is a baseline for community-based intervention. We determined the prevalence of human cysticercosis and associated risk factors following a deworming program conducted throughout the country, with Mbulu District being among the districts in Northern Tanzania. Methods: Human cysticercosis was determined by enzyme-linked immunosorbent assay (Ag- ELISA). Household interviews and observations were conducted to identify risk factors for cysticercosis transmissions among households and communities. Results: Three hundred individuals participated in this study. The age ranged from 5 to 89 years, with a median of 19 years. The prevalence of human cysticercosis was 23 (7.67%). The prevalence was high with 6 (11.76%) among individuals aged 26 to 35 years and ±45 years. There was no statistically significant difference in the prevalence by age group, sex, or occupation. Among the 300 participants, 82 (27.3%) had received anthelmintics during the previous year; among these, 5 (21.7%) were infected. The likelihood of infection was low among anthelmintic users by 28% [0.72 (0.26–2.01)], but the protection was not significant. The communities differed in risk factors on the availability of a clean and safe water supply; 52.7% (46/86) of households visited had no pit latrine. The cysticercosis prevalence showed a significant difference in communities. Conclusions: The prevalence of human cysticercosis was high and associated with higher age groups. The prevalence was low among those who had taken anthelmintics and was associated with lower age groups. The current school deworming program has a positive effect on school children, while the elderly are at higher risk because the intervention did not target them. It is recommended to scale up anthelmintic intervention to higher age groups. Full article

Paslahepevirus balayani and Rocahepevirus ratti are genetically diverse species of hepatitis E virus [HEV]. Previously, only members of the Paslahepevirus genus were known to infect humans but recently some Rocahepevirus members have been found to be infectious to both immunocompromised and immunocompetent humans. Paslahepevirus balayani genotypes (gt) 1, 2, and 4 are known for their detrimental effects during pregnancy, causing pregnancy-related disorders. Recent findings have demonstrated the ability of Paslahepevirus balayani gt3 to replicate within placental cell lines, suggesting a direct effect on the placenta and fetus. To study whether zoonotic rat HEV strains possess a similar human-host placental tropism, we utilized JEG-3 cells to understand the replicative ability of an infectious clone of a recently reported strain of Rocahepevirus ratti, the LCK-3110 strain. Infectious cDNA clones of Pasla-, Avi-, and Rocahepevirus were transcribed and then, transduced into JEG-3 cells. Cells were harvested, and cell lysates were used for testing infectivity. Five days post-transfection or after inoculation onto naive HepG2/C3A cells, the cells were analyzed for infection. Replication in transduced JEG-3 cells and the infection potential in HepG2/C3A cells were assessed via an indirect immunofluorescence assay and a flow-cytometry assay. We found that the Rocahepevirus ratti LCK-3110 strain did not have efficient replication in JEG-3 cell cultures. Full article