Zoonotic Dis., Volume 6, Issue 1 (March 2026) – 10 articles

Background: Human granulocytic anaplasmosis (HGA) is a tick-borne zoonotic infection caused by Anaplasma phagocytophilum and transmitted by Ixodes species. In temperate regions, HGA is considered seasonal, with most cases occurring during late spring and summer. We describe two cases of HGA diagnosed in January during a winter period with episodic temperatures exceeding thresholds for tick activity, highlighting atypical seasonal presentation and diagnostic challenges. Methods: This report details the clinical course, diagnostic reasoning, and management of two patients evaluated at a tertiary care hospital in Suffolk County, New York. Data were derived from direct clinical care and the electronic health record. The institutional review board determined this work did not constitute human subject research. Written informed consent was obtained from both patients. Results: Both patients presented with acute febrile illness and characteristic laboratory abnormalities. Due to winter season, tick-borne infection was not initially suspected, resulting in delayed consideration. PCR testing confirmed A. phagocytophilum infection in Case 1, meeting CDC criteria for confirmed HGA. Case 2 met CDC criteria for probable HGA based on serologic testing showing elevated IgG (1:320) in the appropriate clinical context. Treatment with doxycycline led to rapid clinical improvement and complete recovery. Conclusions: These cases demonstrate that HGA can be diagnosed during winter months in endemic regions. Although the precise timing of infection cannot be determined, these observations occurred during a period when episodic temperatures exceeded thresholds for tick activity. The cases highlight limitations of season-based diagnostic assumptions and suggest maintaining clinical suspicion for anaplasmosis year-round in endemic areas. Full article

Chagas disease, caused by Trypanosoma cruzi, is maintained in nature by complex interactions among wild vertebrates and triatomine insect vectors, yet the role of many introduced hosts remains poorly resolved. Here, we assessed natural T. cruzi infection in wild European rabbits (Oryctolagus cuniculus) from central Chile, where introduced rabbits overlap ecologically with the sylvatic vector Mepraia spinolai. Eight free-ranging rabbits captured in Las Chinchillas National Reserve were evaluated using an integrative diagnostic approach combining xenodiagnosis with laboratory-reared, parasite-free M. spinolai nymphs, real-time polymerase chain reaction targeting T. cruzi satellite DNA in blood and 12–14 organs per animal, and histopathology with immunohistochemistry (anti-cruzipain) to identify tissue parasite forms. Blood molecular detection was positive in seven out of eight rabbits, while xenodiagnosis detected viable parasites in two out of seven evaluated individuals. Organ molecular screening detected T. cruzi DNA in at least one organ in all rabbits, with frequent positivity in the diaphragm, reproductive tissues, spleen, and kidney. Histopathology identified parasite forms in four out of eight animals, and immunohistochemistry confirmed hepatic amastigotes in one case. These findings provide multi-method evidence of natural infection in the sampled individuals, including evidence of parasite viability in some individuals, suggesting potential epidemiological relevance within this ecological context and possible utility for surveillance in Chilean sylvatic transmission settings. Full article

Lassa fever remains a major public health threat in West Africa, yet the household and behavioural determinants of prior Lassa virus exposure are not sufficiently understood. This study examined environmental, behavioural, and demographic factors associated with Lassa virus IgG seropositivity among residents of selected states in North-Central Nigeria. Analysis was carried out on baseline data from 958 participants enrolled in the first phase of an ongoing longitudinal cohort study, which collected information on rodent exposure, house integrity, food safety practices, and household composition. Formative indices were constructed and standardised, and logistic regression models with 1000-iteration bootstrap estimation were used to identify predictors of IgG positivity. Seroprevalence of Lassa virus IgG was 19%, while IgM positivity was 1.15%. Rodent activity around and within homes was widespread, with more than 86% of participants reporting rodent presence. Logistic regression analysis showed that rodent exposure (standardised coefficient 0.20, 95% CI 0.02–0.43) and participant age (0.20, 95% CI 0.05–0.35) were significant predictors of IgG seropositivity. Household size demonstrated a strong inverse association (−0.41, 95% CI −0.68 to −0.20). House integrity and food safety formative indices exhibited weak and non-significant effects. Model performance was acceptable (AUC 0.63; Brier score 0.148), and variance inflation factor values confirmed negligible multicollinearity. These findings emphasised the continuing role of rodent exposure and demographic factors in Lassa virus transmission risk. This implies that there is a need to strengthen community-level rodent control and household-based prevention strategies, which can help to reduce exposure. Full article

Crimean–Congo Hemorrhagic Fever (CCHF) disease, caused by the CCHF virus (CCHFV), poses a significant fatality risk whose underlying pathological mechanisms, including the contribution of coagulation factors, imbalances and platelet abnormalities, remain poorly understood. Here we present a meta-analysis and meta-regression analysis using clinical data from coagulation assays and platelet parameters as predictive disease indices with the goal of uncovering pathognomonic factors and to pave a way for the development of effective therapeutic approaches. Methods: We systematically analyzed published studies reporting coagulation assays and platelet indices in patients with confirmed CCHF. Data from 1779 patients across the published studies were analyzed to assess associations between laboratory parameters and the fatality risk, while evaluating heterogeneity and prognostic significance. Results: Fatal outcomes were strongly associated with elevated liver enzymes (AST: 1116.71 ± 1454.08 IU/mL; ALT: 446.56 ± 457.41 IU/mL) and prolonged clotting times (PT: 19.53 ± 6.57 s; aPTT: 64.02 ± 23.13 s; INR: 1.53 ± 0.56). D-dimer levels did not significantly predict fatality. Thrombocytopenia and coagulopathy emerged as independent risk factors for adverse outcomes. Notably, protein C and protein S levels did not differ between survivors and non-survivors, suggesting that the coagulopathy is not purely consumptive or a result of impaired hepatic synthesis. In contrast, mildly reduced antithrombin levels (83.65 ± 19.90) were weighted toward increased mortality. Full article

Anthrax, caused by Bacillus anthracis, remains a significant zoonotic disease across the globe disproportionately affecting rural populations reliant on livestock farming. Despite the availability of vaccines for humans and animals, and preventive measures, anthrax outbreaks continue to occur due to convergence of inadequate animal husbandry practices, socioeconomic vulnerabilities, and cultural traditions. This study aimed to identify and quantitatively synthesize the key exposure-related behavioral risk factors for human anthrax infection while contextualizing socio-demographic and cultural determinants through narrative review. A systematic review and meta-analysis were performed in accordance with PRISMA guidelines. Using a random-effects model, risk estimates were pooled exclusively for exposure-related behavioral pathways that are mechanistically linked to anthrax transmission, while socio-demographic and cultural variables were summarized narratively due to heterogeneity in study design, variable definition, and limited cross-study comparability. A total of 20 studies were included, primarily from Africa, Asia, and Europe. The meta-analysis identified a consistent set of high-risk exposure pathways, including contact with raw meat from infected animals (OR = 5.79, 95% CI: 4.04–8.31), skinning (OR = 5.64, 95% CI: 3.73–8.52), butchering (OR = 6.54, 95% CI: 3.26–13.09), slaughtering or presence during slaughter (OR = 5.16, 95% CI: 2.54–10.49), and handling of carcasses or animal by-products (OR = 4.13, 95% CI: 2.88–5.92). Socio-demographic and cultural factors, including religious norms and demographic characteristics, were consistently identified as contextual modifiers of anthrax risk across studies but were not quantitatively pooled because of methodological and definitional heterogeneity. While heterogeneity varied by risk factor, it remained generally low to moderate, supporting the consistency of findings across diverse settings. Our findings emphasize that direct exposure-related behaviors represent the dominant and consistent transmission pathways for human anthrax across endemic settings. Effective prevention strategies should prioritize improved livestock management, enhanced biosecurity systems, community education on safe animal handling practices, particularly the handling of moribund livestock or dead animals of unknown origin, and strengthened veterinary services. Future research should prioritize region-specific interventions and conduct longitudinal studies to assess the effectiveness of anthrax risk reduction efforts. Full article

Tuberculosis (TB) remains a major public health challenge, particularly in sub-Saharan Africa, where the emergence of drug-resistant MTB undermines current control efforts. This study aimed to characterize genetic mutations associated with resistance to first- and second-line injectable drugs in MTB isolates from pulmonary TB patients in the Republic of Congo. A total of 45 culture-positive MTB isolates collected between 2018 and 2019 were analyzed using targeted next-generation sequencing on the MinION device. Resistance-associated genes, including rpoB, katG, embB, gyrA, and rrs, were examined. Overall, 22/45 isolates (48%) harbored at least one mutation associated with drug resistance. Among resistant isolates, rifampicin resistance was detected in 15 of 22 (68.2%), predominantly associated with mutations in the rpoB rifampicin resistance–determining region, including p.Ser531Leu, p.Asp516Val, and p.His526Tyr.Ethambutol resistance was observed in 11 of 22 isolates (50.0%) and was mainly associated with the embB p.Met306Val mutation. Isoniazid resistance was detected in 9 of 22 isolates (40.9%), primarily associated with the KatG p.Ser315Thr mutation. Fluoroquinolone resistance was identified in 2 of 22 isolates (9.1%), mainly associated with gyrA p.Ala90Val and p.Asp94Gly mutations. Resistance to second-line injectable drugs was detected in 1 of 22 isolates (4.5%) and was associated with the rrs p.Ala1401Gly mutation. These findings underscore the need to enhance molecular surveillance and strengthen treatment protocols for drug-resistant TB in the Republic of Congo to effectively combat this evolving health crisis. Full article

Background: Africa is a continent with diverse climates, landscapes, rainfall patterns, and vegetation types, all of which significantly influence its mammalian fauna, particularly small mammals. Rodents, which are highly diverse across the continent, serve as reservoirs for various zoonotic pathogens. Frequent human–rodent interactions heighten the risk of zoonotic disease transmission, posing a serious public health concern. Methods: This study conducted a comprehensive review of rodent control methods and their effectiveness in mitigating zoonotic diseases in Africa. Literature searches were performed using PubMed, Web of Science, ResearchGate, and Google Scholar. Additionally, one study was manually identified from the reference lists of the retrieved papers. Results: Thirteen relevant studies were identified, including seven field-based studies, five model evaluations, and one review. The distribution of studies varied by country, with the highest numbers conducted in Guinea (n = 3) and Nigeria (n = 3), followed by Sierra Leone (n = 2), Uganda (n = 2), Morocco (n = 1), Tanzania (n = 1), and Madagascar (n = 1). Two primary rodent control methods, kill traps and rodenticides, were used, targeting multimammate rats (Mastomys natalensis) and black/roof rats (Rattus rattus), the species most frequently encountered in human settings. Conclusion: Most studies examined short-term rodent management strategies, which proved insufficient in significantly reducing zoonotic disease prevalence. These findings highlight the need for Africa to adopt more sustainable, ecologically based rodent control approaches to effectively curb zoonotic risks in the long term. Full article

Background: With the worldwide resurgence of Mpox in 2022, understanding its regional features is important. This systematic review aimed to provide an overview of the epidemiology, risk factors, clinical features, and outcomes of Mpox in Saudi Arabia to fill the knowledge gaps in this area. Methods: Following the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses, a systematic search was performed on PubMed, MEDLINE (via Ovid), Scopus and Wiley Online Library for case reports and series published on Mpox in Saudi Arabia after 2022. Results: Analysis included eight studies comprising a total of 410 patients with confirmatory data. The cohort was predominantly male (91%), with a mean age of 32.8 years. Extramarital sexual contact was the most frequently identified risk factor (28.8%), whereas most patients (63.4%) had unknown or denied exposure routes. The most common clinical manifestations were fever (97.1%) and rash (96.8%). Dermatological findings were usually pleomorphic. These included umbilicated pustules, crusted papules, and vesiculopustular lesions. Although management was primarily supportive, rare complications, such as keratitis and neurological deficits, were observed. Conclusions: In Saudi Arabia, Mpox primarily affects young adult males, particularly individuals with high-risk sexual behaviors. Much of this transmission remains undetermined, and better contact tracing and focused public health efforts are urgently required. Full article

Brazilian spotted fever (BSF) is a tick-borne acute febrile disease that can be lethal to humans, caused by the bacterium Rickettsia rickettsii. In the State of São Paulo, transmission occurs mainly through two tick species: Amblyomma sculptum and Amblyomma aureolatum. We analyzed trends in BSF incidence and mortality in relation to the spatial distribution of these vector species in the State of São Paulo from 2007 to 2017 and evaluated clinical outcomes according to hospitalization location. In A. sculptum areas, incidence and mortality showed significant increasing trends between 2007 and 2015 (p-value < 0.05). In contrast, A. aureolatum areas exhibited a significant decrease in incidence (p-value < 0.05), while mortality remained stable throughout the study period. Lethality was substantially higher in cases associated with A. aureolatum than in those linked to A. sculptum (67.1% versus 55.0%, p-value = 0.037). Most patients received care in hospitals located near the probable site of infection. Incidence and mortality patterns differed sharply between vector-specific areas, with notably higher mortality in A. aureolatum-related cases. These findings highlight the importance of incorporating vector distribution into surveillance, prevention, and clinical management strategies to better address the distinct epidemiological contexts within the State of São Paulo. Full article

Background: Human monkeypox is a zoonotic disease caused by the monkeypox virus (MPXV), endemic in Central and West Africa. A significant 2022 outbreak affected 104 countries, driven by increased susceptibility due to the cessation of smallpox vaccination, global travel, and interactions with infected animals. Strengthening surveillance, public health measures, and raising awareness are essential for early diagnosis, vaccination acceptance, and preventing future outbreaks. Methods: The survey was distributed to 645 nursing students of the University of Palermo between July 2022 and August 2022, and we estimated the knowledge, attitudes and behaviors through a KAP Survey. Descriptive statistics were used to summarize the data, while chi-squared, Fisher’s exact, and Student’s t-tests were employed to analyze differences between groups, with statistical significance set at p < 0.05. At least 80% of the students surveyed had already taken the microbiology exam, as microbiology is studied in the first year of the Bachelor of Science in Nursing program at the University of Palermo. Results: The survey showed a predominantly young, female nursing student population with limited knowledge of monkeypox, as only 3.88% demonstrated adequate understanding. Despite this, attitudes toward prevention were positive, with 82.64% scoring adequately and 41.09% expressing strong willingness to get vaccinated. Knowledge improved with academic progression (p = 0.005), while attitudes and behaviors remained consistent. These findings imply a critical gap in education; the limited knowledge, especially regarding transmission and severity, may lead to an underestimation of the risks associated with global infectious diseases. This underscores the need to better prepare future healthcare professionals for public health emergencies Conclusions: The study found that nursing students had limited knowledge of monkeypox, especially regarding epidemiology and disease severity. Despite positive attitudes toward vaccination, some behaviors reflected an underestimation of global infection risks. Knowledge improved with academic progression, underscoring the importance of education. Targeted educational programs are needed to enhance awareness and preparedness for future outbreaks. Full article