Caracterización y evolución temporal de la mortalidad por zoonosis bajo declaración obligatoria, entre los años 1997 y 2018 / Characterization and temporal evolution of mortality due to zoonoses under mandatory declaration, between the years 1997 and 2018

INTRODUCCIÓN: Las zoonosis son enfermedades transmitidas desde un hospedador animal al ser humano o viceversa. En Chile, las zoonosis de Notificación Obligatoria (NO) son: brucelosis, carbunco, triquinosis, hidatidosis, leptospirosis, dengue, enfermedad de Chagas, hantavirosis y rabia. OBJETIVO: Evaluar la tendencia y caracterizar la mortalidad por zoonosis de NO en Chile entre 1997-2018. METODOLOGÍA: Estudio ecológico de la mortalidad por zoonosis de NO. Se utilizaron bases de mortalidad y población oficiales. Se describió la mortalidad relativa, general y específica, según variables sociodemográficas. Se calcularon tasas de mortalidad anuales brutas (TMb) y ajustadas (TMa, método directo). Se evaluó la tendencia temporal con modelos de regresión de Prais-Winsten. Resultados: Entre 1997 y 2018 la mortalidad por zoonosis de NO correspondió al 0,12% (2.359 muertes) de la mortalidad total, siendo las principales causas la enfermedad de Chagas (59,8%), hidatidosis (23,9%) y hantavirosis (13,8%). La TMa general disminuyó significativamente (B: -0,017; IC95%: -0,024; -0,009) al igual que hidatidosis (B: -0,011; IC95%: -0,013; -0,008), sólo hantavirosis mostró un aumento (no significativo). CONCLUSIÓN: La mortalidad por zoonosis de NO disminuyó durante el período estudiado; solo la hantavirosis mostró un aumento en su tendencia. Se sugiere enfocar estrategias para prevenir la transmisibilidad y mortalidad por hanta, así como mejorar el acceso a tratamiento para las otras zoonosis.

BACKGROUND: Zoonoses are diseases transmitted from an animal host to humans or vice versa. In Chile, the zoonoses of mandatory notification are brucellosis, anthrax, trichinosis, hydatidosis, leptospirosis, dengue, Chagas disease, hantavirosis and rabies. AIM: To assess the trend and characterize the mortality from zoonoses of mandatory notification in Chile between 1997-2018. METHODS: An official mortality and population data were used. Relative, general and specific mortality rates were described according to sociodemographic variables. Crude and adjusted annual mortality rates (direct method) were calculated. Temporal trend was evaluated with the Prais-Winsten regression model. RESULTS: Between 1997 and 2018, the mortality rate due to zoonosis of mandatory notification corresponded to 0.13% (2152 deaths) of the total mortality, being Chagas disease (59.2%), hydatidosis (24.6%) and hantavirosis (13.5%) the main causes. The general adjusted mortality rate decreased significantly (B: -0.017; IC95%: -0.024; -0.009) as did hydatidosis (B: -0.011; IC95%: -0.013; -0.008), and only hantavirosis showed an increase trend (not significant). CONCLUSION: Mortality due to zoonoses decreased during the period; only hantavirosis showed an increasing trend. It is suggested to focus on strategies to prevent contagion and mortality by hantavirosis, as well as to improve access to treatment for the other zoonoses.

[Characterization and temporal evolution of mortality due to zoonoses under mandatory declaration, between the years 1997 and 2018]. / Caracterización y evolución temporal de la mortalidad por zoonosis bajo declaración obligatoria, entre los años 1997 y 2018.

BACKGROUND: Zoonoses are diseases transmitted from an animal host to humans or vice versa. In Chile, the zoonoses of mandatory notification are brucellosis, anthrax, trichinosis, hydatidosis, leptospirosis, dengue, Chagas disease, hantavirosis and rabies. AIM: To assess the trend and characterize the mortality from zoonoses of mandatory notification in Chile between 1997-2018. METHODS: An official mortality and population data were used. Relative, general and specific mortality rates were described according to sociodemographic variables. Crude and adjusted annual mortality rates (direct method) were calculated. Temporal trend was evaluated with the Prais-Winsten regression model. RESULTS: Between 1997 and 2018, the mortality rate due to zoonosis of mandatory notification corresponded to 0.13% (2152 deaths) of the total mortality, being Chagas disease (59.2%), hydatidosis (24.6%) and hantavirosis (13.5%) the main causes. The general adjusted mortality rate decreased significantly (B: -0.017; IC95%: -0.024; -0.009) as did hydatidosis (B: -0.011; IC95%: -0.013; -0.008), and only hantavirosis showed an increase trend (not significant). CONCLUSION: Mortality due to zoonoses decreased during the period; only hantavirosis showed an increasing trend. It is suggested to focus on strategies to prevent contagion and mortality by hantavirosis, as well as to improve access to treatment for the other zoonoses.

Spatial epidemiology of cystic echinococcosis in livestock from a hyper-endemic region in southern Chile.

Cystic echinococcosis (CE) is a parasitic zoonosis, caused by the larval stage of Echinococcus granulosus. This disease has a worldwide distribution and is considered an important zoonosis in Chile, especially in regions where raising livestock dominates. We aimed to describe the spatial distribution and risk factors for CE in cattle and sheep slaughtered in the Aysén Region, Chile between 2015 and 2016, to inform disease control in this hyper-endemic region. Clustering and hotspot analyses of CE at the farm-level were performed (Moran's global index, local indicator of spatial autocorrelation (LISA), and the scan statistic Poisson model), and we used spatial interpolation to display areas with a higher risk of CE. Mixed effects logistic regression models were fit to assess the association between municipality of origin and age of animals and CE detected at slaughter, with the farm of origin included as a random effect. Overall, data from 1532 cattle farms (1078 geocoded) and 30,805 cattle were analyzed, with a 64 % and 39 % CE prevalence at the farm and animal-level, respectively. For sheep farms, data from 381 (296 geocoded) farms and 58,223 sheep were analyzed, with a 71 % and 18 % CE prevalence at the farm and animal-level, respectively. Globally, the CE prevalence in both cattle and sheep farms was not clustered. However, we found 14 cattle and 23 sheep farms with high prevalence that were locally clustered. We also detected 6 and 11 clusters in cattle and sheep farms, respectively. Risk of reported CE varied according to municipalities of origin, and the age of animals. This study confirms that the Aysén region is a hyper-endemic region for CE. It demonstrates the usefulness of the traceability of animals slaughtered for understanding the epidemiology of CE. The results suggest that in this hyper-endemic region in which there are limited financial resources available, that intervention activities - at the beginning of a control program - should be focused on farms with high prevalence and identified disease clusters.