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Brazil Zika cases raise concern of virus transmission beyond mosquitoes

Image: Aedes aegypti mosquitoes are seen inside Oxitec laboratory in Campinas, Brazil, February 2, 2016. REUTERS/Paulo Whitaker


By Anthony Boadle

BRASILIA (Reuters) – Two cases of Zika being transmitted through blood transfusions were reported in Brazil on Thursday, adding to concerns over the virus that has been linked to severe birth defects and is typically spread through mosquito bit’s.

The disclosure of the blood transfusion cases in the industrial city of Campinas near Sao Paulo came two days after Texas authorities said a person became infected through sex. Concern over the virus is mounting as Brazil prepares to host the Olympic Games in August, with tens of thousands of athletes and tourists anticipated.

There is no vaccine or treatment for Zika, which has caused outbreaks in at least 26 countries in the Americas. Brazil researchers hope to develop a treatment that could be tested in humans in a year.

Dr. Marcelo Addas Carvalho, director of the blood center at the University of Campinas, said genetic testing confirmed that a man who received a blood transfusion from a Zika-infected man in March 2015 became infected with the virus, although he did not develop symptoms.

Another man, who had suffered gunshot wounds, became infected with Zika after receiving multiple blood transfusions that included blood don’ted by an infected person in April 2015, Carvalho said.

Carvalho said that infection probably was caused by the transfusion but genetic tests have not yet been conducted to confirm it. He said it was very unlikely the infection was caused by a mosquito bite because the patient was in a hospital intensive care unit for three months.

The patient later died from his gunshot wounds and not the Zika infection, health officials and Carvalho said.

Carvalho sought to downplay the Zika threat arising from blood transfusions, saying such transmission of the virus is very rare and not an important factor in the outbreak.

“Governments and society in general should focus on eliminating the mosquito, which is the main form of transmission,” Carvalho added.

Brazil estimates that up to 1.5 million people have been infected in the country. Brazil is investigating more than 4,000 suspected cases of microcephaly, a condition in which infants are born with abnormally small heads and can suffer developmental problems, that may be linked to Zika.

The World Health Organization said it is strongly suspected Zika causes microcephaly but still must be confirmed scientifically. The U.N. agency declared a global health emergency related to Zika on Monday, citing the microcephaly threat.


Florida Governor Rick Scott on Thursday expanded a Zika public health emergency in the state, adding a fifth locale, Broward County, to the four counties he announced on Wednesday.

“With over 20 million residents and 100 million tourists, we must stay ahead of the possible spread of the Zika virus and take immediate action to ensure Florida is prepared,” Scott said.

Sexual contact and blood transfusions as modes of transmission have been matters of concern for experts since the Zika outbreak’s outset, said infectious diseases expert Dr. William Schaffner of the

Vanderbilt University School of Medicine in Nashville, Tennessee.

But Schaffner questioned whether either will lead to widespread Zika transmission.

“A little bit of transmission? Sure,” Schaffner said. “But the main engine of transmission that has led this virus to be spread widely throughout Central and South America and the Caribbean is, of course, the mosquito.”

Procedures for blood don’tions have been tightened in countries including Brazil to protect blood supplies from Zika. U.S. health officials are still working on national guidelines.

Following word of the Texas case on Tuesday, U.S. health officials urged the use of condoms to prevent spreading sexually transmitted infections.

Brazil said it was reinforcing instructions to blood banks that people infected with Zika or dengue not be permitted to don’te blood for 30 days after full recovery from the active stage of Zika infection.

The American Red Cross has urged prospective donors who have visited Zika outbreak zones to wait at least 28 days before giving blood, but called the risk of transmitting it through blood don’tions “extremely” low in the continental United States.

In the Texas case, authorities said a person in Dallas became infected with Zika after having sex with another person who had traveled in Venezuela, where the virus is circulating.

Local health officials said on Thursday both those people have fully recovered from the virus.

Schaffner said uncertainties remain about sexual transmission of the virus, including how long a person might be able to transmit it or whether an infected person must have had symptomatic Zika in order to be able to transmit Zika through sex. Most infected people do not develop any symptoms.

New York Governor Andrew Cuomo expanded his state’s free Zika testing to include all pregnant women who have traveled to countries where people have been infected.

(Reporting by Anthony Boadle in Brasilia; Additional reporting by Jon Herskovitz in Austin, Texas and Letitia Stein in Tampa; Writing by Will Dunham; Editing by Michele Gershberg, Grant McCool and Lisa Shumaker)

Copyright 2015 Thomson Reuters. Click for Restrictions.

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