Two more countries—the Republic of Trinidad and Tobago and Vietnam—reported suspected Zika-linked microcephaly cases, while a pair of new scientific reports today described further evidence of the virus in semen and vaginal secretions.

In Florida developments, the state reported four new infections contracted in Miami-Dade County, three of them from two known transmission areas.

Microcephaly reports in more countries

A hospital official who leads Trinidad and Tobago's Zika screening program said brain abnormalities were recently detected on the ultrasounds of five unborn babies, at least four of them with Zika as the sole risk factor, the Trinidad and Tobago Guardian reported yesterday. Karen Sohan, MD, said one of the cases may also involve a genetic abnormality unrelated to Zika virus.

Trinidad and Tobago confirmed its first Zika cases 8 months ago, and most of the women who are carrying fetuses that have abnormal ultrasounds were infected before the 18th week of gestation, but at least one of them as late as 25 weeks, according to the report.

Sohan told the Guardian that the brain abnormalities represent a fourfold increase in the number of central nervous system abnormalities seen on ultrasounds.

So far the country has recorded 621 Zika cases among patients in the public health system, 392 of them in pregnant women, according to the report, which said a team from the Pan American Health Organization (PAHO) has sent a team of sonographers to help the fetal medicine unit at Mt Hope Women's Hospital, the country's referral center, with training and to consult on the abnormal brain findings.

On Sep 27, the health ministry reported a baby born with microcephaly, but so far the investigation hadn't found a direct connection to Zika virus. It has asked PAHO for help in assessing the case. Officials said Trinidad and Tobago averages 12 microcephaly cases each year.

Elsewhere, Vietnam today reported a suspected Zika-related microcephaly case in a 4-month-old baby, according to a health ministry statement translated and posted by the infectious disease blog, Avian Flu Diary. The baby was born in Dak Lak province, located in the country's central region. Health officials held an emergency meeting today to discuss the latest development, and the ministry said it expects more Zika cases to be detected, especially in areas where mosquitoes are known to carry dengue and Zika viruses.

Vietnam also reported two more Zika cases, both from Ho Chi Minh City, raising Vietnam's total to seven, according to a report today from Bernama, Malaysia's national news agency, which cited Vietnam News Agency. Four of the cases are from the city, and the three others are from Binh Duong province in the south and the central provinces of Kahnh Hoa and Phu Yen.

In a related development, Venezuela—a country hit by Zika virus that hasn't officially reported any suspected or confirmed microceophaly cases—may have 50 to 60, Reuters reported today, based on media reports and interviews with doctors in two parts of the country. Venezuela's Institute of Tropical Medicine estimates that Venezuela could have 563 to 1,400 microcephaly cases by the end of the year, based on pregnancy rates and Zika-related birth defect numbers in neighboring Brazil.

According to the Reuters report, the government has had a muted response to the Zika outbreak, with some doctors suspecting that officials are hiding the problem. Experts have raised deep concerns about the impact of Venezuela's economic crisis not only on the supply of contraceptives, insect repellent, and tools to battle mosquitoes, but also on medical support for babies and families affected by birth defects.

Scientific studies

Two case reports in Emerging Infectious Diseases today shed more light on viral persistence in semen and vaginal secretions and the role they may play in sexual transmission and passing the virus to fetuses.

In one of them, clinicians from London described lab testing and follow-up of a 45-year-old British man who got sick a day after returning from a 1-week vacation in Rio de Janeiro, Brazil, in February. The man and his partner were eager to conceive and had doubts about whether they needed to wait 6 months, as recommended by Public Health England.

Repeat testing at 22, 55, and 92 days after the man's symptom onset revealed evidence of Zika RNA in the man's semen. However, tests done at day 132 and 174 were negative. As for other similar case reports, virus couldn't be cultured from the patient's semen samples, so it's still not clear if Zika RNA means the patient is still infectious, the team wrote.

Repeat testing was useful for encouraging the couple to wait for two negative results and corresponded to the 6-month waiting period recommended by health officials, the authors noted.

In the second case, a Texas-based research team described lab testing on a 26-year-old woman who got sick 5 days after returning to the United States from Honduras in May. Most of her symptoms were consistent with Zika virus, except for desquamation on the palms of her hands and soles of her feet.

Researchers collected and tested body fluid specimens for the next several weeks to help document the natural history of Zika infection and transmission routes. They detected viral shedding in vaginal secretions up to day 14 after symptom onset, longer than the 11 days seen with an earlier reported case. However, they couldn't determine if the results indicated replicating virus.

In their tests on the woman's whole-blood samples, specimens were positive starting at day 8 and up to 81 days after her symptom onset. The group found that the finding was related to Zika adherence to the erythrocyte component, similar to what's been reported for West Nile virus, another flavivirus.

Tests on day 64 didn't reveal any infectious virus in the erythrocytes, but the authors said the finding is concerning and warrants further testing. They noted that follow-up testing will continue to determine how long viremia lasts in whole blood.

Screening whole blood might be a more sensitive way to identify Zika infection, the authors wrote. Also, the team pointed out the desquamating rash, presumably from the woman's Zika infection, hasn't been described before.

Local Florida cases rise by 4

The Florida Department of Health (Florida Health) today reported four more locally acquired Zika infections. One is linked to the Miami Beach transmission area, two are linked to the newly defined transmission area in Miami-Dade County, and investigators are trying to determine where the fourth person was exposed.

Florida now has 160 local Zika infections, plus 19 more in out-of-state residents who were infected in Florida. The state added one more case to its total for travel-related cases, putting that number at 738, and two more to infections in pregnant women, lifting that total to 108. The state doesn't detail how many of the infections in pregnant women are locally acquired.

See also:

Oct 16 Guardian story

Sep 27 Trinidad and Tobago health ministry statement

Oct 17 Avian Flu Diary post

Oct 17 Bernama story

Oct 17 Reuters story

Oct 17 Emerg Infect Dis report on Zika in semen

Oct 17 Emerg Infect Dis report on Zika in vaginal secretions and whole blood

Oct 17 Florida Health daily Zika update