Zoonotic Dis., Volume 2, Issue 3 (September 2022) – 7 articles

A retrospective study was conducted in 2022 to determine the seroprevalence of brucellosis and its risk factors among goat and sheep herds in the Karenga district, Karamoja region, Uganda. Sera from 332 goats and 81 sheep from 20 kraals in all seven administrative units of the district were tested using the modified Rose Bengal test (mRBT). It was determined that brucellosis was present in 20% of the small ruminant herds in the Karenga district, with an overall animal level seropositivity of 3.39% (CI: 1.87–5.62%; n = 14/413). Higher seropositivity was recorded in goats (3.92%, CI: 2.1–6.6%) than sheep (1.23%, CI: 0.03–6.69%). Similarly, seropositivity was higher in females (3.95%, CI: 2.12–6.66%) than males (1.19%, CI: 0.03–6.456), and also higher in goats and sheep more than two years old (4.15%, CI: 2.09–7.31%) than those one to two years old (1.98%, CI: 0.24–6.97%) or those less than one year old (2.13%, CI: 0.05–11.29%). Only herd size was statistically significant (p < 0.05) as a risk factor for exposure to brucellosis in the Karenga district. Although the prevalence of brucellosis among goats and sheep in the Karenga district is low, there still exists a risk to the pastoralists who closely interact with the animals and also practice risky behaviours such as consumption of uncooked or unpasteurised goat milk. There is need to expand herd health messaging in Karenga to include risk communication on brucellosis and other zoonotic diseases. Full article

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has produced five variants of concern (VOC) to date. The important spike mutation ‘N501Y’ is common to Alpha, Beta, Gamma, and Omicron VOC, while the ‘P681R’ is key to Delta’s spread. We have analysed circa 10 million SARS-CoV-2 genome sequences from the world’s largest repository, ‘Global Initiative on Sharing All Influenza Data (GISAID)’, and demonstrated that these two mutations have co-occurred on the spike ‘D614G’ mutation background at least 5767 times from 12 May 2020 to 28 April 2022. In contrast, the Y501-H681 combination, which is common to Alpha and Omicron VOC, is present in circa 1.1 million entries. Over half of the 5767 co-occurrences were in France, Turkey, or US (East Coast), and the rest across 88 other countries; 36.1%, 3.9%, and 4.1% of the co-occurrences were Alpha’s Q.4, Gamma’s P.1.8, and Omicron’s BA.1.1 sub-lineages acquiring the P681R; 4.6% and 3.0% were Delta’s AY.5.7 sub-lineage and B.1.617.2 lineage acquiring the N501Y; the remaining 8.2% were in other variants. Despite the selective advantages individually conferred by N501Y and P681R, the Y501-R681 combination counterintuitively did not outcompete other variants in every instance we have examined. While this is a relief to worldwide public health efforts, in vitro and in vivo studies are urgently required in the absence of a strong in silico explanation for this phenomenon. This study demonstrates a pipeline to analyse combinations of key mutations from public domain information in a systematic manner and provide early warnings of spread. The study here demonstrates the usage of the pipeline using the key mutations N501Y, P681R, and D614G of SARS-CoV-2. Full article

Ticks and tick-borne pathogens are increasing public health threats due to emergence of novel pathogens, expanding geographic ranges of tick vectors, changing ecology of tick communities, as well as abiotic and biotic influences on tick–host–pathogen interactions. This review examines the major human-biting ixodid tick species and transmitted pathogens of North America. Topics addressed include current and projected tick geographic ranges, potential risks for introduction of tick transmitted microbes into those regions, and drivers for these events. Health care providers, public health authorities, and the general public need to be aware of existing, resurging, and emerging tick and tick-borne disease threats. Knowing which ticks and tick-borne pathogens are present is foundational to understanding and responding to these threats. Dominant tick species and pathogens remain major foci of research, while limited attention has been directed to other human-biting ticks for decades, resulting in questions about current distributions, population sizes, and diversity of infectious agents they are capable of transmitting. Significant threats due to invasive ticks are considered. Recommendations are made for establishment of a sustained North America network for surveillance of ticks, characterization of their microbiomes and viromes, and for support of tick and tick-borne disease ecology research. Full article

Japanese encephalitis (JE) is a mosquito-borne zoonotic disease that causes severe brain inflammation. The JE virus envelope protein domain III (JEV-ED3) plays a critical role in activating receptor binding and membrane fusion. This communication briefly describes, in a computational approach, how structural changes within the JEV-ED3 mutant epitopes suppress their antibody neutralization function. The simulated results demonstrate that mutant Ser40Lys acts as an antibody neutralization escape while Asp41Arg may play the role of an escape mutant. Additionally, an examination of the double mutants on JEV-ED3 suggests that these mutants may qualify as stronger neutralizing escape agents than their single variants. The structural analysis of this work helps to identify the proper antiviral target sequences and specific monoclonal antibodies for the JEV-ED3 escape mutants. Full article

Migrant and seasonal workers in the United States, among others in rural agricultural communities, may be at an elevated risk for tick-borne diseases (TBDs). This research included a survey of over 250 such workers, both women and men, in 13 locations across five eco-systems in Texas, which is generally perceived as a non-endemic state. Employing a modified Horowitz Multiple Systemic Infectious Disease Syndrome Questionnaire, a range of data was collected regarding living conditions, such as sleeping outside, along with queries about tick exposure, tick bite encounters, illnesses, and prior TBD diagnoses. Findings revealed that 67% of the respondents who scored highest on symptom severity suggestive of a TBD reported sleeping outdoors (compared to 29% of the lowest scoring), with 78% of the likely-to-highly-likely group also recalling tick-bite encounters (compared to 20% of the lowest scoring). Approximately 28% of those who reported severe symptoms also indicated previous Lyme disease diagnoses. This research serves as an initial investigation into the living conditions associated with increased risk of TBDs among vulnerable populations. It underscores the need for further assessments of TBD risk relative to vulnerable populations even in perceived non-endemic regions and highlights the paucity of actionable data as a critical public health issue. Full article

As the spread of canine leishmaniasis (CanL) is increasing throughout the world, the need for effective agents to prevent its transmission has intensified. In this case report, an intact 1.5-year-old male French bulldog was presented for treatment of severe, sudden, and constant lameness on his right hindlimb, which had started approximately four months previously and was unresponsive to routine nonsteroidal anti-inflammatory drugs. A Neem oil-based product was sprayed three times a week on the dog’s coat for about fourteen months as the only prophylactic measure against CanL. The orthopedic examination revealed grade 3–4 lameness and marked atrophy of the thigh muscles with swollen and painful right stifle joint. The radiological investigation showed polyostotic periosteal proliferation at both hindlimbs. The diagnosis of CanL was established by examination of fine-needle aspiration of lymph nodes (left prescapular, right and left popliteal) and immunofluorescence antibody testing. A leishmanicidal therapeutic protocol was prescribed. Within ten days of starting the therapy, the dog was significantly less lame, and eight months later radiographic examination revealed complete regression of the bone lesions. Some owners resort to a naturalistic approach for CanL prevention, also using products that have not been clinically evaluated. Neem oil is thought to prevent sandfly bites in dogs. Some laboratory and field studies have identified Neem oil as a possible alternative herbal drug that is repellent to sandflies. However, the clinical, laboratory, and radiographic findings clearly show that the Neem oil spray formulation used in this case report was not an effective means of CanL prevention. There is no clinical evidence in support of Neem oil-based products for the protection of dogs against CanL transmission. As Neem oil has previously been shown to be somewhat volatile, this case report suggests that even though it is a very effective repellent against sandflies, in practice, its effect on the dogs’ coat was only short-lived. Full article

The aim of this study was the examination of the genetic diversity and antimicrobial susceptibility of C. jejuni isolates obtained from dairy farms situated in Cantabria. The presence of Campylobacter jejuni was scrutinized in dairy farms situated in the Cantabria region (Atlantic coast, North of Spain). A total of 520 samples were collected from 12 dairy farms and 62 C. jejuni isolates were achieved. Sixty-one (61) of the isolates proceeded from fresh feces and only one from the stable (soil). Characterization of the isolates was conducted by Pulsed Field Gel Electrophoresis (PFGE) analysis. Antimicrobial susceptibility testing was carried out by standardized disk diffusion test. The PFGE analysis showed a high genetic diversity. From the 62 C. jejuni isolates, 27 different PFGE types were obtained with 70% similarity. The results of the antimicrobial susceptibility tests showed that 21 out of 27 strains were resistant to ciprofloxacin (78%), and 15 of them were also resistant to tetracycline (55%), whereas none of the 27 strains analyzed were resistant to erythromycin. C. jejuni was capable of surviving in livestock waste for at least 20–25 days, whereas the maximum detectable survival time on crops was of six days. This study reveals the high genetic diversity and ciprofloxacin resistance of C. jejuni in dairy cattle farms in Northern Spain, a fact that highlights the urgent need for the surveillance and control of this foodborne pathogen. Full article