Brazilian authorities have not addressed the longstanding issues that led to the Zika epidemic in the country, leaving it vulnerable to another outbreak of the virus, according to a Human Rights Watch report released this week.

"There is this idea that Zika is gone, the emergency has been lifted," said Amanda Klasing, senior women's rights researcher at Human Rights Watch and co-author of the report. "But the risk for another outbreak is there."

Despite declaring an end to the national public health emergency over the mosquito-borne virus in May, systemic problems with public water and sanitation systems remain, the report said. More than one-third of Brazilians lack access to a continuous water supply, so many must fill tanks and other containers with water, which can become potential mosquito breeding grounds if they are not treated or covered.

Researchers also described seeing untreated sewage flowing near communities that were often obstructed by debris, creating dirty, standing water – also ideal conditions for breeding of the Aedes aegypti mosquito, the primary transmitter of the virus.

"The Aedes mosquito is programmed to breed in standing water close to the human populations," said William May, the co-director of the Johns Hopkins Zika Centre and an associate professor of ophthalmology at the Johns Hopkins Wilmer Eye Institute, who travels often to lecture in Brazil.

The Zika virus is alarming because it is linked to a birth defect known as microcephaly, which results in smaller heads and brain damage in infants. It has also been linked to infant eye abnormalities and Guillain-Barr Syndrome, a neurological disorder where the body's immune system attacks the nerve cells, causing weakness and, sometimes, temporary paralysis. There is no vaccine to prevent Zika and no treatment for microcephaly.

Brazil's Health Ministry said in a statement on Thursday that the administration has increased spending on improving basic sanitation and water facilities, along with budgeting more for health surveillance, including controlling mosquito populations.

However, Human Rights Watch said too much of Brazil's work has focused on the household level, such as encouraging families to clean their water storage containers and eliminate standing water in their homes. That places too much of the burden on women and girls and "cannot fill the gap left by inadequate government action," the report said.

Researchers urged the government to decriminalise abortion, saying criminal penalties force women and girls to turn to secret and often unsafe procedures to terminate unwanted pregnancies. In Brazil, abortions are illegal except in cases of rape, incest, danger to the mother's life or anencephaly, a brain defect in the fetus. A July 2016 study in the New England Journal of Medicine found a 108% increase in requests during the Zika outbreak to a non-profit organisation providing abortion medications.

The report also called on the government to give more financial and logistical support to the caregivers of the over 2,600 babies born with microcephaly and other Zika-related conditions.

Caring for a baby with Zika syndrome is expensive, noted May. "They have seizures and feeding problems," he said. "They require special formula and they require anti-seizure meds."

"(The families) really need more help," he added.

In the US, Zika cases declined dramatically since last year. In 2016, there were over 5,000 cases reported, 224 of them acquired through local mosquitoes, according to the Centres for Disease Control and Prevention (CDC). The total number has dropped to 163 this year, and none of those cases were acquired locally, though some questions have been raised about the timeliness of the CDC's 2017 data.

"In the United States, it is the travel-related cases that come up," said May, referring to people who go abroad and bring the virus home with them. "Because we have wonderful health departments, we been able to control the virus so far."

Thomas Skinner, a spokesperson for the CDC, said he wouldn't be surprised if they did see a few cases of local transmission later this year. But the agency is prepared.

"The CDC has good surveillance systems in place. We have good control programs that can jump into action," he said.

USA Today