Simposio: Enfermedades zoonóticas (rabia, hidatidosis, entre otros)

SIMPOSIO

Enfermedades zoonóticas (rabia, hidatidosis, entre otros)

COORDINA: Nidia Aréchiga & Graciella Santillán

Enfermedades zoonóticas (rabia, hidatidosis y otras zoonosis)

Una Salud es un enfoque esencial que integra la salud humana, animal y ambiental. La conciencia sobre la interconexión entre ellas es clave para desarrollar estrategias más eficaces en la lucha contra las enfermedades. En este Simposio se abordarán la Rabia, la Equinococosis quística (Hidatidosis) y otras enfermedades zoonóticas desde la perspectiva de Una Salud, y se discutirán los desafíos que representan para su prevención y control.

Rabia

La rabia en gatos se ha convertido en un motivo de preocupación a nivel mundial, ya que los gatos domésticos actúan como vectores de diversos lisavirus prevalentes en sus regiones geográficas. Se han documentado casos de rabia humana vinculados a gatos en África, Asia, Europa y América. Como cazadores hábiles y solitarios, tanto los félidos silvestres como domésticos son susceptibles a la infección por lisavirus, la cual puede producirse a través de la interacción con presas infectadas, como los murciélagos, o mediante la transmisión por otros mesocarnívoros, incluidos perros, zorros, chacales, mapaches y zorrillos rabiosos.

Equinococosis quística / Hidatidosis

La equinococosis quística es un problema de salud pública en América del Sur. Está catalogada como una enfermedad desatendida por la Organización Panamericana de la Salud, cuyo plan de acción para el control y erradicación de esta infección parasitaria incluye la vigilancia, diagnóstico, manejo y prevención de casos en humanos. Esto comprende la desparasitación de perros con praziquantel y la vacunación rutinaria de ovejas con la proteína recombinante EG95, o una combinación de ambas estrategias. También existen medidas complementarias, como el desarrollo de infraestructura sanitaria en los establecimientos rurales, la educación para la salud, y la búsqueda activa de casos asintomáticos y su tratamiento oportuno.

Palabras clave: rabia, hidatidosis, zoonosis.

Rabies in felines: emerging vectors in the urban rabies cycle in Mexico

GARCÉS, Fabiola¹; SALGADO, Aurea¹; ALMAZÁN, Cenia¹; OLAVE Ignacio²; AGUILAR, Alvaro³; LÓPEZ, Irma¹; ARÉCHIGA, Nidia¹.

¹ Instituto de Diagnóstico y Referencia Epidemiológicos. Mexico City, Mexico.
² Instituto de Ciencias Agropecuarias, Área Académica de Medicina Veterinaria y Zootecnia, Universidad Autónoma del Estado de Hidalgo. Tulancingo, Hidalgo, Mexico.
³ Programa de Maestría y Doctorado en Ciencias de la Producción y de la Salud Animal, Unidad de Posgrado, UNAM. Mexico City, Mexico
E-mail address: garces.fabiola23@gmail.com

Felines (wild-living and urban) are not natural reservoirs of rabies virus variants (RVV). However, they have become emerging transmission vectors to humans and other mammals in the Americas. In northern Mexico, between 2000 and 2021, six rabies cases occurred in pumas (Puma concolor), restricted to the states of Sonora and Chihuahua. They were antigenically and genetically characterized, and five out of six samples corresponded to RVV7 (associated with the Arizona gray fox) and one to RVV1, associated with dogs. Since the 1990s, there has been no evidence of RVV1 circulation in dogs in the northern states, skunk species now harbor this variant in the region. Although pumas are not rabies virus reservoir, they represent a risk of transmission for humans and animals. Their behavior enables them to spread the virus across multiple species over relatively large areas. Oral vaccination of rabies reservoir species, mainly gray foxes (Urocyon cinereoargenteus) and skunks species in Sonora and Chihuahua, may be the most viable alternative for controlling rabies in pumas. Furthermore, population growth in the state of Yucatan has led to construction in the Mayan jungle for residential spaces, tourist attractions, and agriculture. This coincides with an increase in cat (Felis catus) rabies cases between 2003 and 2022, with 9 registered cases. Three antigenic variants have been identified in the region: RVV1 associated with dogs (n=1), RVV3 associated with vampire bats (n=1), and the canine-originated atypical variant (n=7). Phylogenetic analyses suggest two epidemiological cycles of the virus. The first one involves hematophagous bats (Desmodus rotundus), which harbor the rabies virus in the state, and the second one corresponds to a mammalian terrestrial cycle. The atypical variant is believed to have its reservoir in wild-living species, particularly skunks. Since this variant is canine-originated, there is a high risk of reintroducing the virus into canine populations if vaccination coverage is not maintained. In recent years, in our country, there have been four cases of human rabies transmitted by felines, one by a puma in Chihuahua, and by cats in Quintana Roo (2) and Nayarit (1). This demonstrates that rabies in felines could represent a significant risk of transmission to humans, so it is important to maintain vaccination coverage in all susceptible species, especially dogs and cats. Epidemiologic surveillance is required to anticipate future rabies virus emergence and to identify new reservoir species.

Keywords: Rabies, Feline, Spillover.

Impact of Feline Rabies on the Transmission Dynamics of Zoonotic Diseases in Colombia

MERIÑO, Samir E^1-2

¹ IMPRONTA, Universidad Cooperativa de Colombia Campus Ibagué-Espinal. Ibagué, Colombia.
² CENTAURO, Universidad de Antioquia, Medellín, Colombia
E-mail address: samir.merino@campusucc.edu.co – samir.merino@udea.edu.co

Introduction: Feline rabies, although reported less frequently than canine rabies, represents an emerging and significant public health concern, particularly in countries like Colombia, where rabies cases continue to be reported in various regions. Unlike dogs, whose role in rabies transmission has been extensively documented and addressed through mass vaccination campaigns, the role of domestic and free-roaming cats has received comparatively little attention. However, cats can serve as important epidemiological links between sylvatic reservoirs—especially hematophagous and insectivorous bats—and human populations, acting as silent amplifiers within urban and peri-urban environments. The presence of unvaccinated and unregulated cat populations increases the likelihood of spillover events, especially in areas where interactions between wildlife, domestic animals, and humans are frequent. Despite being underreported, feline rabies cases have been associated with documented human exposures, underscoring the need to reevaluate current rabies prevention strategies. Incorporating cats into systematic surveillance and vaccination programs is essential for reducing the risk of zoonotic transmission and aligning control efforts with a One Health perspective. Objectives: To evaluate the impact of feline rabies on the transmission dynamics of zoonotic diseases, particularly in urban and peri-urban contexts with high levels of cat–human interaction. Material and Methods: A retrospective analysis of rabies surveillance data reported in Colombia was conducted, including the identification of confirmed feline rabies cases. This information was complemented with spatial mapping and risk modeling to detect areas of increased human exposure and interspecies transmission events. Results: Clusters of rabies cases in cats were identified, associated with an increase in human exposures, particularly in areas with low vaccination coverage, high bat presence, and unregulated feline populations. Peri-urban zones showed the highest levels of risk. Discussion: The findings highlight the emerging role of cats as amplifying hosts in the transmission dynamics of rabies. Gaps in control programs, limited vaccination coverage in felines, and the absence of policies for the management of community cats pose significant challenges for prevention. Conclusions: Feline rabies plays a critical role in zoonotic transmission in Colombia. It is essential to strengthen epidemiological surveillance, systematically include cats in rabies vaccination campaigns, and implement integrated strategies under a One Health approach that links human, animal, and environmental health sectors.

Keywords: Rabies, Zoonoses, Feline.

Changing epidemiological profile of rabies in Brazil: emergence of human cases caused by bat variants transmitted by cats

ROCHA, Silene Manrique¹, VOIETTA, Fernanda Pinna¹

¹ Ministry of Health, Secretariat of Health Surveillance and Environment, Brasília, Brazil.
E-mail address: Silene Manrique Rocha _silene_rocha@hotmail.com

While dog-mediated urban rabies has been largely controlled in Brazil, sylvatic rabies remains a significant public health concern. Since 2000, there has been a marked epidemiological shift, with bat-associated antigenic variant 3 (AgV3) now responsible for the majority of human cases. From 2000 to 2025, 51.9% of the 212 confirmed human rabies cases were linked to AgV3; 4.6% of these were transmitted by domestic cats. In the same period, 408 cats tested positive for rabies, and approximately 10% of genotyped samples were associated with bat variants.Cats are increasingly recognized as secondary vectors for bat-derived rabies, primarily due to their predatory behavior and ecological overlap with bats in urban areas. This trend reflects broader environmental and societal changes, including deforestation, urban expansion, and habitat disruption, which have facilitated the adaptation of bats to urban ecosystems. These factors, combined with limited public knowledge about feline rabies risks and post-exposure prophylaxis, contribute to increased vulnerability.This scenario calls for integrated, multisectoral strategies grounded in the One Health approach. Priorities include improving rabies vaccination coverage among cats, strengthening epidemiological surveillance, raising public awareness about feline rabies, and addressing the environmental factors that drive interspecies viral transmission. The growing interface between bats, cats, and humans—especially in urban settings—represents a key challenge for rabies prevention and control in Brazil.

Keywords: Cats, Zoonoses, One Health

Geospatial tools for the surveillance of parasites of public health concern

AVILA, Héctor Gabriel^1,2, ANES, Paola Emilce¹, SANDON, Leonardo³ & PERIAGO María Victoria^2,3

¹ Laboratorio Provincial de Zoonosis, San Juan, Argentina.
² CONICET, CABA, Argentina.
³ Fundación Mundo Sano, CABA, Argentina.
E-mail address: hectorgabrielavila@gmail.com

Helminth parasites have life cycles that can be influenced by environmental conditions, canine soil-transmitted helminth (cSTH) parasites need specific environmental conditions to complete their life cycle. Toxocara spp is the most important zoonotic cSTH, since it is the causal agent of human toxocariasis. This zoonotic disease is among the top 5 neglected parasitic diseases worldwide. In this study, the presence of cSTH in canine feces was evaluated in 34 crowded public parks and squares from San Juan Province (Argentina). Fecal samples were collected during different seasons in 2021-2022 and analyzed by standard coprological methods. Weather data analyzed were: mean temperature, diurnal temperature variation, accumulated precipitation, air humidity, cloud cover, solar energy, and wind speed. The correlation between Toxocara spp eggs presence and a composite remote sensed index, which can be identified as a proxy for tree shadow, was analyzed. This new index, specifically created for this study, was named the Tree Magnitude Index (TMI) and it is calculated through the multiplication of the Topographic Index Position obtained from a Digital Surface Model and the Normalized Difference Vegetation Index (NDVI) obtained from satellite imagery. The TMI was treated as a response variable and as an explanatory one, using the difference between the observed and expected value of positive cases, assuming a homogeneous distribution. From a total of 1121 samples collected, 100 (8.9%) were positive for at least one intestinal parasite and three cSTH species were detected: Toxocara spp, Toxascaris leonina and Trichuris vulpis. The most prevalent cSTH species was T. vulpis (64/1121; 5.7%), while the least prevalent was T. canis (19/1121; 1.7%). The detection of Toxocara spp eggs was significantly higher during autumn (χ2=16.34, df=3, p < 0.001), where higher humidity values were also recorded. Using simple linear regression, the TMI significantly predicted Toxocara spp prevalence (R² = 0.67, F(1, 10) = 23.2, p < 0.01), with the following fitted regression model: Δ Observed-Expected Value = 0.54 + 0.81*(TMI). This is the first study in San Juan to identify environmental contamination of cSTHs in public areas. The specific localization of squares and parks with the presence of cSTH eggs aim to provide information to design strategies to lower the cSTH infection burden in dogs and to provide information to direct serological screening of the human population for Toxocara spp. Given the zoonotic nature of these cSTHs, we hope this information be useful for monitoring other parasites and will help to reinforce activities of control programs, focusing on the «One Health» approach.

Keywords: Geospatial tools, zoonotic parasites, One Health.

Molecular surveillance in cystic echinococcosis: Advanced tools for the diagnosis and control of Echinococcus

Astudillo Osvaldo G¹, Moreno Yanina¹,Diego Gustavo R¹, Cabrera Marta¹

¹National Institute of Infectious Diseases. ANLIS Dr. Carlos G. Malbrán
Email: gastudillo@anlis.gob.ar

Cystic echinococcosis (CE), caused by Echinococcus granulosus, is an endemic parasitic zoonosis in several regions of South America. Its life cycle involves dogs as definitive hosts, sheep as intermediate hosts, and humans as accidental hosts. Epidemiological surveillance relies on detecting canine infections through coprological and molecular analyses. The objective of this study was to compare the performance of 11 diagnostic methods applied to canine fecal samples, aiming to improve epidemiological surveillance of echinococcosis using a Bayesian Latent Class Model (BLCM) to estimate the sensitivity (Se) and specificity (Sp) of each technique. A total of 68 dog fecal samples were collected from rural areas linked to a clinical case in a child under 15 years old. The following methods were evaluated: M1) Modified Telemann (Se 75%, Sp 99%), M2) Willis flotation (Se 74%, Sp 99%), M3) Sheather (Se 70%, Sp 99%), M4) Direct microscopy (Se 95%, Sp 100%), M5) cox1 PCR (Chelex) (Se 89%, Sp 80%), M6) cox1 PCR (N2 Elu) (Se 92%, Sp 81%), M7) LAMP COI (EGSL) (Se 92%, Sp 92%), M8) LAMP (Abbasi) (Se 94%, Sp 90%), M9) DCO1 specific PCR (Se 80%, Sp 95%), M10) Copro-PCR (Abbasi) (Se 88%, Sp 90%) and M11) EGSL 3.0 (Se 94%, Sp 89%). All values included 95% confidence intervals. The BLCM was implemented with MCMC simulations, assigning informative priors to Se and Sp based on scientific literature. This model estimates the probability of infection without requiring a gold standard. The estimated prevalence among sampled dogs was 5.2%. Molecular methods (M5–M11) outperformed classical coproparasitological techniques (M1–M4) in sensitivity. Among them, LAMP methods (M7, M8) and the improved EGSL 3.0 (M11) stood out for achieving high Se (>90%) and good Sp (89–92%). In contrast, classical methods like M1–M3, while highly specific, showed poor sensitivity (<75%), reducing their utility in low parasite burden scenarios. The inclusion of molecular diagnostics, particularly specific PCR and LAMP EGSL technology, significantly enhances the detection of E. granulosus in canine hosts, who play a key role in transmission. Active surveillance with high-performance methods is critical for the accurate identification of infection hotspots and the strategic planning of control interventions in endemic regions.

Keywords: Echinococcosis, Molecular diagnostics, Surveillance

A look at cystic echinococcosis from the perspective of climate change

SANDOVAL, Alejandra E.^{1 2}

1. Jefatura Provincial Zoonosis. Secretaria de Salud. Chubut Patagonia Argentina
2. Facultad de Ciencias Naturales y Ciencias de la Salud. Universidad Nacional de la Patagonia San Juan Bosco. Chubut Patagonia Argentina.
E-mail address: zoonosischubut@gmail.com

Over the past five post-pandemic years, we have rethought the role of leading public health programs in Chubut, focusing on climate change. The growing recognition of climate change as a problem whose nature is framed within an epistemic area and a reality that affects both human and natural systems opens a window for dialogue between scientists from different disciplines. This work aims to shed light on the processes and mechanisms that underlie climate change and hydatidosis. It is crucial to generate a perspective on new scenarios and transform the view of hydatidosis, reduced to bioclinical dimensions, from a comprehensive perspective, beyond the threat-risk limits, but rather through its relationship to ecological and sociocultural components, which will explain and anticipate vulnerability related to climate change and this parasitic zoonosis.
To explore knowledge linking climate change and hydatidosis over the last 5 years.
To describe approaches and processes linking climate change and hydatidosis.
Qualitative study, bibliographic review, and content analysis. The following questions are posed: How has research linking climate change and hydatidosis been approached? In what way or manner was this research addressed? The search was conducted using the keywords «climate change and hydatidosis.» Publications were reviewed in the PubMed database; the final search was conducted in July 2025.
The information was organized into a matrix: title, year and geographic area studied, general description of the research, objectives, results, and conclusions.
Eleven articles were retrieved, two excluded by title and abstract. Of the remaining seven, two non-Open Access works were discarded.
Their titles highlight the link between climate change and the transmission and distribution of echinococcosis. General descriptions mention factors that favor the spread of hydatidosis, influences on egg survival, host alteration, and interactions. Emphasis is placed on aspects related to climatic factors, such as temperature and humidity, land use, vegetation cover, seasonal variations, and resource availability. The objectives were to understand, evaluate, estimate, and explore ecological processes that influence transmission patterns. Methodologies emphasized the review of bioclimatic variables for statistical modeling with real data or literature reviews. One of the works included anthropogenic practices such as hunting. The results emphasized the key role of anthropogenic factors related to climate change and ecosystems. Models with positive and negative impacts on echinococcosis were described. Conclusions highlighted the need for government support, further research for risk management and social impacts, and highlighted environmental changes. Mitigation strategies focused on education and surveillance, working from a health and eco-health perspective.
Today, we will have to rethink analyzing climate change scenarios from an integrated vulnerability perspective in our regional context.

Keywords: echinococcosis, climate change, zoonosis, vulnerability

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