Serologic survey of hantavirus in a rural population from the northern State of Mato Grosso, Brazil

INTRODUCTION: Hantavirus is a genus of ribonucleic acid (RNA) viruses included in the family Bunyaviridae. Hantaviruses are rodent-borne zoonoses that, in the last 18 years, became an emergent public health problem in the Americas, causing a severe cardiopulmonary syndrome. This disease has no specific treatment and has a high case fatality. The transmission of hantavirus to man occurs by inhaling aerosols of rodent excreta. The aim of this study was to determine the prevalence of antibodies to hantavirus in the population of the rural settlement of Tupã in the county of Marcelândia, state of Mato Grosso, Brazil. METHODS: The participants of the serologic survey were visited at their homes and selected randomly among the settlement population. Blood samples of the participants were collected by venopuncture. The serum samples were tested by an IgG-ELISA using an N recombinant protein of Araraquara hantavirus as antigen, using the protocol previously established by Figueiredo et al. RESULTS: IgG antibodies to hantavirus were detected in 7 (13%) of the 54 participants. The positivity was higher among men. It was observed that there was an association of seropositivity to hantavirus within the participants born in the south of Brazil. CONCLUSIONS: The results suggest that, in this rural area, everyone is exposed to the same risk of becoming infected with hantavirus, and, therefore, there is a need to intensify surveillance activities and education of the local people to prevent this viral infection.

Características de Oligoryzomys longicaudatus asociadas a la presencia del virus Andes (Hantavirus) / Oligoryzomys longicaudatus characteristics' associated with the presence of Andes virus (Hantavirus)

Oligoryzomys longicaudatus is the main reservoir of Andes virus (AND), which causes hantavirus pulmonary syndrome in Patagonia. The factors associated with the presence of antibodies against AND in this species are unknown. This study used a logistic regression model to analyze which characteristics of O. longicaudatus, captured in northern Argentinean Patagonia, led to an increased probability of an animal having antibodies against AND and to relate these characteristics to possible mechanisms of transmission of the virus within the population. Sex, age, body mass, and wounds were important predictors regarding the presence of antibodies against AND within O. longicaudatus populations. The probability of a wounded male O. longicaudatus adult having AND antibodies increased in parallel with the body mass. The probability of having antibodies was more than 80% in individuals with body masses above 44 gram. However, the possible transmission mechanism of AND within O. longicaudatus population is still uncertain and further studies involving a larger number of individuals and prolonged monitoring including the process of seroconversion are needed.

Oligoryzomys longicaudatus es el principal reservorio del virus Andes Sur (AND) causante del síndrome pulmonar por hantavirus en la Patagonia. Aún se desconoce qué características individuales están asociadas a una mayor presencia de anticuerpos contra AND en esta especie. En este estudio, mediante un modelo de regresión logística evaluamos qué características de O. longicaudatus, capturados en la Patagonia norte de Argentina, incrementan la probabilidad de un individuo de presentar anticuerpos contra AND para relacionarlos con posibles mecanismos de transmisión del virus dentro de la población. El sexo, la edad, la masa corporal y las heridas resultaron factores importantes para la circulación y persistencia del virus dentro de la población de O. longicaudatus. La probabilidad de que un O. longicaudatus, macho, adulto con heridas presente anticuerpos contra AND aumentó con el incremento de la masa corporal, siendo esta probabilidad mayor al 80% en individuos con masas corporales mayores a 44 g. Sin embargo, el posible mecanismo de transmisión de AND dentro de la población de O. longicaudatus queda aún incierto, por lo que son necesarios estudios futuros que involucren un mayor número de individuos y un tiempo prolongado de seguimiento en su proceso de seroconversión.

A questão ambiental na promoção da saúde: uma oportunidade de ação multiprofissional sobre doenças emergentes / Environmental issues on health promotion: a multi-professional action on emerging diseases

A discussão sobre a emergência de agravos à saúde coloca todos os profissionais de saúde em alerta. Através de uma revisão sobre os conceitos de doença emergente, relacionando-a com uma situação concreta, a emergência da hantavirose em Santa Catarina, Brasil, constatou-se a necessidade de um enfoque sobre as condições ambientais em tais situações. O melhor conhecimento sobre os fatores ambientais envolvidos e contextualizados torna possível um melhor posicionamento para a elaboração das políticas de controle e prevenção a serem adotadas. Tal posicionamento possibilita a ação multiprofissional, sob a forma de orientação às comunidades, como necessidade de um modelo assistencial diferenciado.

The discussion on the emergence of health injuries preoccupies all health workers. In a review on the concepts of emerging disease, related to a concrete situation, the emergence of the Hantaviruses in the State of Santa Catarina, Brazil, the author highlights the need for focusing on environmental conditions in such situations. The best knowledge on environmental factors makes it possible to elaborate controlling and preventive policies. This enables the multi-professional action in providing community information, as the need for a differentiated assistance model.

Detección retrospectiva de infecciones clínicas por hantavirus en la Argentina / Retrospective detection of hantavirus clinical infections in Argentina

La actividad de los hantavirus en la Argentina en roedores y humanos ya era conocida desde la década de 1980. En este trabajo, se investigó retrospectivamente la infección por hantavirus entre los pacientes notificados para Fiebre Hemorrágica Argentina (FHA) entre 1987 y 1994, sin confirmación virológica. La detección de anticuerpos IgG e IgM antihantavirus se realizó por técnica de ELISA. Entre 1028 pacientes estudiados se encontraron 13 infecciones recientes (1,26 por ciento) y 13 remotas (l,26 por ciento). Entre 745 personas sanas procedentes de las mismas localidades de los casos de infección reciente, sólo se encontraron anticuerpos IgG en una (O,13 por ciento). De las 13 infecciones recientes, 9 se presentaron como FHSR y 4 como SPH. Se realizó una comparación clínica y epidemiológica entre los 9 pacientes con FHSR y dos grupos control apareados: uno de casos de FHA y otros considerados Síndrome febril de etiología indeterminada (SFEI), que fueron negativos para Hantaan, Junín y Linfocoriomeningits (LCM). No se encontraron diferencias entre los signos y sintomas clínicos. Para el diagnóstico diferencial resulto sugerente la presencia de leucocitos normales o aumentados, con plaquetopenia, hemoconcentración, creatininemia aumentada y proteinuria en las FHSR. Estos resultados muestran la coexistência dentro del área endémica de FHA de virus Junín y hantavirus, e indican la necesidad de incluir a las infecciones por estos virus en el diagnóstico diferencial de las Fiebres Hemorrágicas y de los Síndromes de Distrés Respiratorio de etiología desconocida. La variabilidad clínica encontrada sugiere la presencia de más de un serotipo de hantavirus en nuestro país.

Serological evidence of human hantavirus infection in Argentina, Bolivia and Uruguay

A serological survey was conducted in 1985-1987 to determine the presence of infection for Hantavirus in the general population in Argentina, Uruguay, Paraguay and Bolivia, as well as among rodent-exposed laboratory workers in Argentina. Out of 748 individuals tested by immunofluorescence 20 proved positive for Hantaan virus 76/118 strain of whom 16 also reacted against Seou virus 80/39 strain and 2 against Puumala virus Sotkamo strain. Ten out of 72 Argentine laboratory workers were positive for the first 2 viruses by ELISA, immunofluorescence and/or plaque reduction neutralization test, in 4 of whom recent infection was demonstrated by IgM antibody presence. Inapparent Hantavirus infection was thus demonstrated for the first time in 2.7 per cent of regional inhabitants, together with 13.9 per cent among rodent-exposed laboratory workers. Our data established the existence of human Hantavirus infection nearly 10 years before the recognition of clinical cases of hemorrhagic fever with renal syndrome and hantavirus pulmonary syndrome in Argentina.