Young Researcher Award: Study may help control measures against HTLV virus

Publicação: 15 de September de 2015

Research shows high prevalence of the virus in a Japanese community in Campo Grande

The HTLV-1 infection was detected in 34% of the studied subjects. The phylogenetic analysis associated to the epidemiological data suggested family transmission

The HTLV is a virus that infects the human T-cells, important for the organism’s defense system, although still poorly known among its hosts. It belongs to the HIV’s family, however, it is older and most of the infected people do not develop any disease. However, the development of diseases could lead to death, making it a public health issue. To help the control measures, it is fundamental to develop studies on the matter. This June, one of these works, a master’s thesis dissertation by Larissa Melo Bandeira, now a doctorate student in Infectious and Parasitic Diseases, ranked third place in the 2015 Young Researcher Award.

The focus was the virus’ prevalence among Japanese immigrants and their descendants in Campo Grande (MS). The results may help drawing prevention and control measures against the infection in this community.

“The project’s idea came up from the fact that type 1 HTLV has already been described in Brazil, for the first time, in a Japanese community living in Campo Grande, in 1986. 28 years after its identification, our team became interested in studying this infection’s current epidemiology in the same community”, Larissa explained.

The Okinawan immigrant population is considered vulnerable to HTLV infection due to its origins in the Okinawa islands, an endemic region in Japan where the virus’ prevalence can shift from 14% to 31%. In Campo Grande, the second largest Okinawan community in Brazil.

The doctoral candidate studied the virus’ type 1 infection, which is related to severe degenerative neurological (tropical spastic paraparepsis) and hematological diseases, as leukemia and human adult t-cell lymphoma (ATL). Worldwide, over 10 million people are currently infected, from which only 2% to 3% will develop ATL and from 1% to 2% will develop tropical spastic paraparepsis.

A total of 219 Japanese immigrants and descendants, or family members living in Campo Grande, were interviewed and blood-tested. All samples were submitted to anti-HTLV-1/2 antibody detection, using the enzyme immunoassay method (ELISA) and confirmed by immunoblot method.

“The global HTLV-1 infection prevalence was 6.8%. This rate is considered to be high, and from 40 to 52 times higher than those from blood donors (0.17%) and pregnant women (0.13%) from Campo Grande”, explained the researcher. After a textual analysis of the behavioral risk factors, it was observed that aging 45-years or more is related to the HTLV-1 virus infection.

During the phylogenetic relation study among the HTLV isolates, 38 members of 5 family groups of the investigated population – 20 male and 18 female individuals, identified from 5 positive anti-HTLV-1 index cases.

“The HTLV-1 infection was detected in 34% of the studied subjects. The phylogenetic analysis associated to the epidemiological data suggested family, pointing sexual and vertical [mother to child] as important HTLV-1 transmission routes among the studied population”, said Larissa.

The researcher had collaboration of pharmacists, nurses and physicians. The work, guided by Dr. Ana Rita Coimbra Motta, was developed from April 2012 to October 2013.