Viruses detected in China infect cow fleas in Brazil

Publicado em 10 abril 2019

Lice are hematophagic ectoparasites which feed on vertebrate blood. They are vectors of various types of microorganisms that cause diseases that attack horses, cows, dogs, cats and mice, and also humans.

Cattle infestation (Rhipicephalus microplus) is an infectious disease that causes severe losses to livestock.

The investigation, led by virologists from the Ribeirão Preto School of Medicine, from the University of São Paulo (FMRP-USP), in Brazil, expanded knowledge of the diversity of viruses that infect these fleas.

In a new work, the results of which were published in the journal Scientific Reports, scientists claim to have it identified for the first time in Brazil and in South America for certain pathogens so far only found in China. Among them were the Lihan virus (from the Phenuiviridae family) and the Wuhan virus 2 (from the Chuviridae family).

The authors also described three new tymoviruses (from the order of Tymovirals) called Guarapuaba 1, 2 and 3. The metagenomics technique was used to investigate the diversity of viruses present in the Rhipicephalus microplus found in cattle found in cattle from southern Brazil. This work is supported by FAPESP – the Supporting Foundation for the Scientific Research of the State of São Paulo.

"We identified two almost complete sequences and four partial genomes from Wuhan 2 (WTV-2), family-owned viruses recently described and called Chuviridae. These viruses share between 97% and 98% of amino acid identities with WTV-2. those identified in R. microplus collected in China. These results indicate that WTV-2 is widespread among cow fleas in the southern region of Brazil, "he said. William Marciel de Souza, the first author of the work, from the FMRP-USP Virology Research Center.

For its part, the Lihan virus (LITV) shows a fairly similar pattern among Brazilian ticks.

"We identified an almost complete sequence of two lineages and a partial genome of four types of flebovirus species sharing between 97% and 98% amino acids with LITV described in R. microplus collected in China. As with Wuhan 2, these results indicate that Lihan is spread among cow fleas in the southern region of Brazil, "explained Marciel de Souza.


"Since 2013, the Virology Research Center has carried out, with the support of FAPESP, a large prospect of new viruses that might be important for the health of Brazilian society.

Within the framework of this project, more than 150 new viruses have been identified in vertebrates (rats, bats and others) and invertebrates. The work now published is the first result of arbovirus studies on fleas, "said the expert.

Arbovirus is transmitted by arthropods. Some emerging viruses transmitted by fleas have caused epidemics of deadly and often fatal diseases, which is why they represent serious public health and animal health problems in many regions of the world.

At present around 900 species of lice are known, which are classified into three families: Argasidae, Ixodidae and Nuttalliellidae. Viruses that are transmitted to humans from the bite of infected fleas are mainly found in the Ixodidae family, where the genus Rhipicephalus is located.

Regarding viruses, at least 38 species transmitted through ticks are known to date. They were distributed in eight families, and among them were families (Flaviviridae and Phenuiviridae) from new virus species found by Ribeirão Preto researchers.


Most of the fleas analyzed by the researchers were infected by another virus, jingmen (JMTV), from the same family as the dengue fever and yellow fever (Flaviviridae).

"Flavivirids have a unique genome. What distinguishes JMTV circulating in Brazil is that the genome is divided into four separate segments. Also, phylogenetic trees show that circulating JMTV in Brazil is a genotype that may be different than previously described in Asia," the researchers said. .

"The JMTV virus was detected in cattle fleas in China and also in monkey fleas in Costa Rica. Our virus is 99% similar to that found in China. In Africa there are also very similar. JMTV is in all states in the southern region of Brazil, and we "he estimates that he has a wide distribution throughout the country. We believe that where there is a cow flea virus exists," he said.

According to the virologist from FMRP-USP, identification of viruses in Brazil that were previously only known in China is proof that fleas will arrive in Brazil with the introduction of livestock.

Maybe it can be found all over the world in the tropical and subtropical zones and this tick species, "de Souza concluded.

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