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Visceral leishmaniasis is a neglected zoonotic disease that affects animals and humans in different tropical and subtropical regions and even beyond, with variable prevalence among infected hosts. To date, there have been no systematic reviews on human visceral leishmaniasis prevalence in Latin America. We therefore performed a systematic literature review with meta-analysis, using six databases to assess prevalence of visceral leishmaniasis in human patients in Latin American countries. Observational studies were included but analyzed separately. We performed a random-effects model meta-analysis to calculate the pooled prevalence and 95% confidence interval (95%CI). In all, 10,435 articles were retrieved for the time frame (1950-2019). After initial screening, 120 articles were selected for full-text assessment, 97 being finally included for qualitative and quantitative analyses. Overall, VL pooled prevalence was estimated at 38.8% (95% CI 33.8-43.8%), derived from 97 studies, including 44,986 individuals. Many aspects of the transmission dynamics of Leishmania and the exact burden of this parasitosis on public health remain largely unknown. Although the elimination of zoonotic VL in the Americas appears an unrealistic goal, additional efforts need to be put in place to achieve better diagnosis, treatment, and prevention of VL.

Introduction: Coronaviruses are zoonotic viruses that include human epidemic pathogens such as the Middle East Respiratory Syndrome virus (MERS-CoV), and the Severe Acute Respiratory Syndrome virus (SARS-CoV), among others (e.g., COVID-19, the recently emerging coronavirus disease). The role of animals as potential reservoirs for such pathogens remains an unanswered question. No systematic reviews have been published on this topic to date., Methods: We performed a systematic literature review with meta-analysis, using three databases to assess MERS-CoV and SARS-CoV infection in animals and its diagnosis by serological and molecular tests. We performed a random-effects model meta-analysis to calculate the pooled prevalence and 95% confidence interval (95%CI)., Results: 6,493articles were retrieved (1960-2019). After screening by abstract/title, 50 articles were selected for full-text assessment. Of them, 42 were finally included for qualitative and quantitative analyses. From a total of 34 studies (n=20,896 animals), the pool prevalence by RT-PCR for MERS-CoV was 7.2% (95%CI 5.6-8.7%), with 97.3% occurring in camels, in which pool prevalence was 10.3% (95%CI 8.3-12.3). Qatar was the country with the highest MERS-CoV RT-PCR pool prevalence: 32.6% (95%CI 4.8-60.4%). From 5 studies and 2,618 animals, for SARS-CoV, the RT-PCR pool prevalence was 2.3% (95%CI 1.3-3.3). Of those, 38.35% were reported on bats, in which the pool prevalence was 14.1% (95%CI0.0-44.6%)., Discussion: A considerable proportion of infected animals tested positive, particularly by nucleic acid amplification tests (NAAT). This essential condition highlights the relevance of individual animals as reservoirs of MERS-CoV and SARS-CoV. In this meta-analysis, camels and bats were found to be positive by RT-PCR in over 10% of the cases for both; thus, suggesting their relevance in the maintenance of wild zoonotic transmission.