Epidemiology of zoonotic tick-borne diseases in Latin America: Are we just seeing the tip of the iceberg?

Antibody Seroprevalence to Spotted Fever Group Rickettsiae in Miraflores, Colombia: A Cross-Sectional Study in Humans and Dogs

Tick-borne disease burdens are increasing globally, impacting mostly rural and vulnerable communities. Among the most important emerging tick-borne pathogens are the Rickettsia species within the spotted fever group (SFGR) because of their genetic diversity and high lethality rate. Colombia is highly affected by SFGR despite not being reportable diseases; thus, research and clinical management are neglected. Although some departments have demonstrated high seroprevalence rates, in others, such as Boyacá Department, seroprevalence is unknown. Rickettsioses have not been described in Boyacá since 1943, and conversations with local physicians raised suspicions of recent undiagnosed disease compatible with rickettsiosis in some rural areas of the department, warranting epidemiological investigation. Using biobanked human and canine samples from a previous 2021 vector-borne disease study in Miraflores municipality, Boyacá, we had an opportunity to unearth SFGR's exposure in the region. Samples were evaluated using IgG indirect fluorescent assays against SFGR and complemented by survey questionnaires evaluating associated factors. Findings yielded first-time SFGR serological evidence in Boyacá with a 26.5% seroprevalence among dogs and a 20.4% among humans. Human and dog seroprevalences were positively associated, suggesting the presence of domestic transmission. Owning a greater number of domestic animals (prevalence ratio adjusted for all measured factors [aPR], 1.52) and living near crop fields (aPR, 7.77) were associated with an increased likelihood of household seropositivity. Our findings are consistent with the literature in Colombia, uncovering a suspected region where the disease is endemic. Future studies are warranted to continue defining high-risk areas to determine public health intervention plans.

Tick-borne viruses and their risk to public health in the Caribbean: Spotlight on bats as reservoirs in Cuba

In recent decades, tick-borne diseases (TBDs) have surged and expanded globally due to factors like changes in human activities, land use patterns, and climate change, and it have been associated with the emergence of zoonotic diseases. Cuba faces the impact of ticks on human health and the economy. Although Cuba has studied TBDs extensively for the past 50 years, focus on tick-borne viral pathogens affecting humans remains scant. Despite TBDs not currently being a major health concern in Cuba, factors like inadequate clinician awareness, climate conditions, global tick emergence, and evidence of zoonotic pathogens in ticks underscore the importance of enhanced TBD surveillance in the country. Here we revised the available information on ticks as vectors of pathogenic viruses to humans, spotlighting bats as potential reservoirs of tick-borne viruses (TBVs). Ticks on bats have gained interest as potential reservoirs of pathogenic viruses to humans in Cuba and worldwide. Understanding their role in maintaining viruses and their potential transmission to humans is crucial for the implementation of surveillance and control programs to reduce the risk of tick-borne viral diseases and public health management.

Historical overview and update on relapsing fever group Borrelia in Latin America

Relapsing fever group Borrelia (RFGB) are motile spirochetes transmitted to mammalian or avian hosts through the bite of hematophagous arthropods, such as soft ticks (Argasidae), hard ticks (Ixodidae) and the human clothing lice. RFGB can infect pets such as dogs and cats, as well as birds, cattle and humans. Borrelia recurrentis, B. anserina and B. theileri are considered to have worldwide distribution, affecting humans, domestic birds and ruminants, respectively. Borrelia spp. associated with soft ticks are transmitted mainly by Ornithodoros ticks and thrive in endemic foci in tropical and subtropical latitudes. Nowadays, human cases of soft tick-borne relapsing fever remain neglected diseases in several countries, and the impact these spirochetes have on the health of wild and domestic animals is largely understudied. Human infection with RFGB is difficult to diagnose, given the lack of distinguishing clinical features (undifferentiated febrile illness). Clinically, soft tick or louse-borne relapsing fever is often confused with other etiologies, such as malaria, typhoid or dengue. In Latin America, during the first half of the twentieth century historical documents elaborated by enlightened physicians were seminal, and resulted in the identification of RFGB and their associated vectors in countries such as Mexico, Panama, Colombia, Venezuela, Peru and Argentina. Almost 80 years later, research on relapsing fever spirochetes is emerging once again in Latin America, with molecular characterizations and isolations of novel RFGB members in Panama, Bolivia, Brazil and Chile. In this review we summarize historical aspects of RFGB in Latin America and provide an update on the current scenario regarding these pathogens in the region. To accomplish this, we conducted an exhaustive search of all the published literature for the region, including old medical theses deposited in libraries of medical academies. RFGB were once common pathogens in Latin America, and although unnoticed for many years, they are currently the focus of interest among the scientific community. A One Health perspective should be adopted to tackle the diseases caused by RFGB, since these spirochetes have never disappeared and the maladies they cause may be confused with etiologies with similar symptoms that prevail in the region.

The Impact of Deforestation, Urbanization, and Changing Land Use Patterns on the Ecology of Mosquito and Tick-Borne Diseases in Central America

Central America is a unique geographical region that connects North and South America, enclosed by the Caribbean Sea to the East, and the Pacific Ocean to the West. This region, encompassing Belize, Costa Rica, Guatemala, El Salvador, Honduras, Panama, and Nicaragua, is highly vulnerable to the emergence or resurgence of mosquito-borne and tick-borne diseases due to a combination of key ecological and socioeconomic determinants acting together, often in a synergistic fashion. Of particular interest are the effects of land use changes, such as deforestation-driven urbanization and forest degradation, on the incidence and prevalence of these diseases, which are not well understood. In recent years, parts of Central America have experienced social and economic improvements; however, the region still faces major challenges in developing effective strategies and significant investments in public health infrastructure to prevent and control these diseases. In this article, we review the current knowledge and potential impacts of deforestation, urbanization, and other land use changes on mosquito-borne and tick-borne disease transmission in Central America and how these anthropogenic drivers could affect the risk for disease emergence and resurgence in the region. These issues are addressed in the context of other interconnected environmental and social challenges.

Current distribution of selected canine vector-borne diseases in domestic dogs from Barranquilla and Puerto Colombia, Atlántico, Colombia

Background

Climate change, the increase of travel with infected animals from endemic areas, the introduction of new vectors in these areas and environmental changes caused by human activity, among other factors, have contributed to the establishment and increase of canine vector‐borne diseases (CVBDs), several of which are zoonotic and pose a risk to the human population. In Colombia, there are very few studies that address the prevalence of these diseases. The objective of this study was to update the prevalence of cardiopulmonary dirofilariosis, anaplasmosis, ehrlichiosis and Lyme borreliosis in dogs in Barranquilla and Puerto Colombia, areas of northern Colombia.

Materials and methods

The present study included 354 dogs presented to veterinary clinics for routine health examination and foundations for stray dogs between November 2016 and July 2018.

Results

The percentage of dogs positive for Ehrlichia spp. was 61.86%, followed by 22.03% for Anaplasma spp., 11.30% positive for Dirofilaria immitis antigens and 0.56% positive for Borrelia burgdorferi. In addition, several dogs positive for antibodies against two or more infectious diseases were found. Higher seroprevalences were documented in outdoor dogs compared to indoor‐housed dogs.

Conclusion

These results suggest that veterinarians should routinely implement prophylactic programmes for these CVBDs, particularly for dogs that reside outdoors.

Trends and Opportunities in Tick-Borne Disease Geography

Tick-borne diseases are a growing problem in many parts of the world, and their surveillance and control touch on challenging issues in medical entomology, agricultural health, veterinary medicine, and biosecurity. Spatial approaches can be used to synthesize the data generated by integrative One Health surveillance systems, and help stakeholders, managers, and medical geographers understand the current and future distribution of risk. Here, we performed a systematic review of over 8,000 studies and identified a total of 303 scientific publications that map tick-borne diseases using data on vectors, pathogens, and hosts (including wildlife, livestock, and human cases). We find that the field is growing rapidly, with the major Ixodes-borne diseases (Lyme disease and tick-borne encephalitis in particular) giving way to monitoring efforts that encompass a broader range of threats. We find a tremendous diversity of methods used to map tick-borne disease, but also find major gaps: data on the enzootic cycle of tick-borne pathogens is severely underutilized, and mapping efforts are mostly limited to Europe and North America. We suggest that future work can readily apply available methods to track the distributions of tick-borne diseases in Africa and Asia, following a One Health approach that combines medical and veterinary surveillance for maximum impact.

Typhus Group Rickettsiosis, Brazilian Amazon

Rickettsia rickettsii infection is the only rickettsiosis included in the list of reportable diseases in Brazil, where typhus group rickettsioses, mainly murine typhus, have been underreported. We report a case of typhus group rickettsiosis with unique ecologic particularities in a patient from the Brazilian Amazon, where, to our knowledge, rickettsioses have not been reported.

Status of Anaplasma spp. infection in domestic ruminants from Iran: A systematic review with meta-analysis

Anaplasma species are tick-borne pathogens that are obligatory intracellular of ruminants and other mammalians. In this investigation, we systematically reviewed the distribution of anaplasmosis among domestic ruminants in Iran. Five and four English and Persian databases were studied, respectively, based on keywords and throughout 17 years (2001–2017). Thirty-eight articles were included in this systematic review and meta-analysis. Totally, 5093 cattle, 1958 sheep, and 1232 goats corresponding to prevalence of Anaplasma infection from different areas of Iran were examined. The total prevalence of Anaplasma infection was estimated to be 34% (95% CI 27%, 41%) in domestic ruminants. Based on our data, Khozestan (54%) and Khorasan Razavi (46%) provinces were the most prevalent areas in Iran and Kerman (3%) and Hamedan (1%) provinces are the lowest. The highest prevalence of Anaplasma spp. infection was belonged to A. ovis (44%) and the lowest to A. phagocytophilum (1%) with a significant difference among them (p < .001). In addition, the most common diagnostic tests were PCR (54%), microscopy (35%) and ELISA (7%) assays. The high prevalence of ovine and bovine anaplasmosis in Iran, confirms the stability situations of animal anaplasmosis in the studied regions particularly northeastern and southwestern parts of the country. Our data offer valuable and encouraging information as regards the current situation of anaplasmosis in domestic livestock in Iran, which might be useful for active and passive surveillance and preventing plans.