Hantavirus: a pathology of low prevalence and high mortality

Publicação: 5 de June de 2019

According to the World Health Organization (WHO), the mortality rate of this disease is 38% and there is no treatment, cure or vaccine for the infection

In Brazil, between 2007 and 2015 13.181 cases of the disease were reported, of which 8% were confirmed and 410 deceased

Severe viral disease transmitted by rodents, hantavirus has recently caught the eye in southern Argentina. What surprised was the high concentration of cases in the same locality, with large number of deaths in a short period of time. The World Health Organization (WHO) has issued a warning about the deadly outbreak of hantavirus and warned health authorities in the country to stay vigilant and intensify efforts to detect, investigate, manage and control cases. The WHO also recommended special attention to travelers from the affected areas.

To discuss the topic, the leading specialists in the subject of Argentina and Chile met in Bariloche, at the first Patagonian Congress of Hantavirus, where they discussed the different stages of approaching the disease. Among the activities that took place between the May 23rd and 24th, a document of consensus between the parties was prepared, which includes transparent recommendations of high methodological quality that will be used to make decisions.

The medical director at Hospital Zonal Bariloche (in Spanish), Dr. Fernando Tortosa, explained that the congress addressed several issues related to hantavirus problems in terms of prevention, environmental health, epidemiology, early detection and therapeutic approach. According to him, the ultimate objective was to create a bi-national commission to solve this subtype of virus and develop a consensus document with high-quality, transparent methodological recommendations to assist in decision-making.

As for the work methodology, Dr. Tortosa said that they are working in different groups with intense training and experience in Argentina and Chile, whose objective is to bring together the different thematic groups, such as epidemiology, field approach, molecular biology, virology and development of new therapies. According to the specialist, the idea is to connect people who are working in different fields at all stages of the disease.

Regarding the difficulties of access to research funding, he acknowledged that the pharmaceutical industry opts for those treatments that have high demand, so it is important to establish collaborative support among regional governments and encourage research. He stressed the importance of establishing protocols that allow a rapid response to the disease, as well as achieving a network of epidemiological surveillance between the two countries.

“Also during the last Congress held in the city of San Carlos de Bariloche, recommendations with GRADE methodology on the use of Ribavirin in patients in the viraemic phase or incubation with viral detection by real-time PCR were developed with the support of experts from Argentina and Chile or in the prodromal phase with ELISA for positive IgM or positive RT-PCR. In the same way, it will continue in the region with the development of research on the use of this drug. In addition, a consensus guide on the hantavirus of the Southern Andes was developed in this space with this modern methodology for the development of recommendations”, added Dr. Tortosa

Treatment with ribavirin

After the outbreak of hantavirus that began on December 3 in the small town of Epuyén, in the province of Chubut, southern Argentina, where 3.500 people live, considered the most serious in the history of local health, four people treated with an antiviral drug known as “ribavirin” showed a positive evolution. According to a report posted on the Argentinean site Perfil, after consulting international organizations about the application of ribavirin to the scenario presented, they decided along to the Ministries of Health of La Nación, Chubut and Río Negro, to use the drug. Ribavirin is an antiviral prescribed to combat conditions such as hepatitis or severe cases of some respiratory infections that prevent the spread of the virus within the body. To the moment there are no global recommendations for use in cases of hantavirus, since there is no scientific evidence to support its use. However, the fact may provide authorities with a possible investigation into the treatment of this condition in the absence of a specific drug to combat it.

Rapid test to detect Hantavirus may help reduce mortality

By the end of this year, the creation of a high-precision rapid test for Hantavirus detection can become a reality. Chilean researchers from the Macrozona Sur Reference Center (in Spanish) use reagents identified in the Los Ríos region to improve protocols for detecting the disease. This is the result of a project started in 2015 by the laboratory of virology of the Institute of Microbiology of Universidad Austral de Chile, which in 2016 detected the reactive systems of the strain hantavirus Andes. This variant of the disease is transmitted through the species Oligorizomys longicaudatus, better known as a long-tailed rat, present in the Atacama region (south). After its approval by the Institute of Public Health (ISP), it is expected to begin its patent phase and select a distribution model in Chile and Argentina, where this strain of the virus is present.

There is no treatment, cure or vaccine for hantavirus infection and, according to WHO, the mortality rate is 38%. It is common for cases of hantavirus to be reported every year in South American countries, including Brazil. According to the article Magnitude and distribution of deaths due to hantavirosis in Brazil, 2007-2015, by epidemiological researchers Lidsy Ximenes Fonseca , Stefan Vilages de Oliveira and Elisabeth Carmen Duarte in Brazil, 13.181 cases of hantavirosis were reported in this period, of which 8% were confirmed and 410 died. The authors concluded that high lethality in certain population groups, months of the year and regions of Brazil points to low clinical suspicion of the disease in poorly exposed groups, which may compromise their adequate management.

Source: MoH Portal

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Hantavirus is present in the urine, saliva or excrement of certain wild rodents, especially in North and South Americas. It is transmitted to humans by inhalation of dust or droplets from infected animals, followed by direct contact (with lesions) with contaminated material or by ingestion of contaminated food or water. The illness is characterized by headaches, dizziness, fever, nausea, diarrhea and stomach pain, followed by the sudden onset of severe respiratory symptoms.

In Argentina, from 2013 to 2018, an average of 100 annual cases of hantavirus were recorded. During these years, a total of 111 died of the disease, which has a fatality rate near 20%, but that can reach 40% in some regions in the south of the country. For more information, access the article by Dr. Leticia Ceriani published on the website of the Iberian American Society of Scientific Information (SIIC) entitled “Hantavirus: as an absent state aggravates epidemiological situations.

Physicians from Argentina and Chile, united against hanta. The outbreak last summer in Epuyén triggered the need to share experiences and unify treatments. The lack of patients is the main obstacle.

RECOMMENDATION FOR THE USE OF RIBAVIRIN IN PATIENTS WITH HANTAVIRUS: FROM EVIDENCE TO DECISION