Hantavirus Pulmonary Syndrome in Uberaba, Minas Gerais, Brazil

Vol. 97(6): 783-787, September 2002

Mario León Silva-Vergara⁺, José Carlos Costa Júnior, Cristina Hueb Barata, Vítor Guilherme Maluf Curi, Carlos Giovanni Tiveron Júnior, Alan César Teixeira

Disciplina de Doenças Infecciosas e Parasitárias, Departamento de Clínica Médica, Faculdade de Medicina do Triângulo Mineiro, Av. Getúlio Guaritá s/nº, 38001-970 Uberaba, MG, Brasil

This report describes the epidemiological and clinical-evolutive characteristics of eight patients with hantavirus pulmonary syndrome (HPS) in Uberaba, Minas Gerais, Brazil. A positive history of contact with rodents was present in 100% of the cases. The time between the onset of symptoms and hospital care was, on average, 3.6 days. All patients showed clinical and laboratory findings suggestive of HPS. Elevated urea and creatinine levels were observed in 6 (75%) cases, PO₂ was < 60 mmHg in 100% of the cases, and a chest X-ray demonstrated a bilateral interstitial-alveolar infiltrate. The diagnosis was confirmed by the detection of IgM antibodies against Sin Nombre virus by ELISA. Three patients died as a direct consequence of HPS.

Key words: hantavirus - hantavirus pulmonary syndrome/HPS - Sin Nombre virus - Minas Gerais - Brazil

Since the report of the first outbreak of hantavirus pulmonary syndrome (HPS) in New Mexico, USA (CDC 1993), more than 200 cases have been notified in that country (Van Bevern 2000). Later on, other countries on the American continent also reported the occurrence of cases, mainly Brazil, Canada, Argentina, Chile, and Paraguay, among others (Lopez et al. 1996, Johnson et al. 1997, Vasconcelos et al. 1997). After the identification of the Sin Nombre virus, which belongs to the family Bunyaviridae, as the etiologic agent of HPS, eight hantavirus subtypes and about 16 serogroups, each with a specific wild host, were identified (Bouloy & Zeller 2000). In the case of the American hantaviruses, these hosts belong to the order Rodentia, family Muridae, subfamilies Sigmodontinae, Arvicolinae (Microtus pennsylvanicus related to Prospect hill virus) and Murinae (Rattus norvegicus that transmits Seoul virus, Pereira 1999). Rodents become chronically infected and excrete the virus for several weeks through saliva, feces and urine. In addition, viral antigen has been detected in different organs of these animals, mainly lungs, spleen, liver and kidney (Green et al. 1998). Recent phylogenetic studies have shown amazing superposition of mitochondrial DNA among hantaviruses and their wild hosts, demonstrating the co-evolution of these two species throughout millions of years (Zhao & Hay 1997) and human hantavirus infection is probably very old, but remained unrecognized as a nosologic entity for a long time. Humans are infected through inhalation of aerosols contaminated with saliva, feces or urine of the rodent host. Other routes of infection such as rodent bites and contact between humans are less likely (Le Gueno 1998).

Alterations in the equilibrium of rodent populations and in their interaction dynamics with humans determine the occurrence of hantavirus outbreaks, a situation favored by the large and severe changes in the ecosystem during the last decades (climate changes, deforestation accompanied by the introduction of agricultural practices in these areas, etc.) (Figueiredo et al. 2001).

In Brazil, 171 cases had been notified by the end of 2001 (data obtained from the National Health Foundation) in different states: Paraná (59 cases), Minas Gerais (19), São Paulo (28), Rio Grande do Sul (23 cases), Santa Catarina (22), Mato Grosso (14), Pará (2), and Maranhão, Bahia, Rio Grande do Norte and Goiás (1 case each). In Ribeirão Preto, São Paulo, eight cases were reported during the last few years and in the Triângulo Mineiro Region, several cases were observed in Uberlândia and, more recently, in Uberaba (Figueiredo et al. 2001, Ferreira et al. 2001, Silva-Vergara et al. 2001). We describe here the clinical-epidemiological profile of patients with HPS.

POPULATION AND METHODS

RESULTS

DISCUSSION

ACKNOWLEDGMENT

To Maria Rita de Souza for preparation of the manuscript.

REFERENCES

Figure | Table I | Table II | Table III | Table IV

⁺Corresponding author. Fax: +55-34-3318.5279. E-mail: dip_fmtm@mednet.com.br

Received 28 December 2001

Accepted 15 May 2002