Ground Zero | Stopping the virus — muddled science, poor public health communication mar India’s response to Zika outbreak

Field note: “It is tough to say how big a risk Zika will be to India in the coming days. For now, the two outbreaks, in Rajasthan and Madhya Pradesh, appear to be relatively small.” A scene at Kothari, one of the Zika affected villages in Madhya Pradesh.   | Photo Credit: A.M. Faruqui

Maya Madan, 22, lives in a brick hut in Hamid Khedi village. A few feet from her home, which is in Sehore district of Madhya Pradesh, is a narrow street, criss-crossed by ditches full of dirty water. The buzz of mosquitoes breeding in these pools fills the air. It does not come entirely as a surprise that several of the cases of the State’s first and India’s second Zika outbreak are from Hamid Khedi and its neighbouring hamlets. Zika is spread by the mosquito species, Aedes aegypti. It thrives in stagnant water.

Even though the Zika virus only causes mild fever and symptoms such as rashes in most people, Madan has more to worry about as she is three months pregnant. The virus has been linked to birth defects in 5%-15% of children of infected mothers. Such birth defects include an abnormally small head (microcephaly), eye damage, shortened muscles and joints, and hearing damage.

This is why the World Health Organisation (WHO) recommends that in areas with ongoing Zika transmission, pregnant women should be made aware of Zika’s dangers. They must use mosquito nets and repellent. Given that Zika can spread through sexual activity, they should avoid unprotected sex, while couples planning to have children should consider delaying pregnancies. Yet, 18 days into the outbreak, Madan hasn’t heard anything about it. In fact, public communication about the virus seems to be limited to mosquito-control alone, with no mention of the other ways in which it can spread. Zika has the unique property of causing birth defects, which other mosquito-borne diseases do not. Yet, recently painted signs on the village walls warn about dengue and malaria, but are silent about Zika.

Misinterpreted science

The Madhya Pradesh Public Health & Family Welfare Department’s reluctance to counsel citizens quickly is due to an odd misinterpretation of Zika research. On November 3, 2018, a press release from the Ministry of Health and Family Welfare cited the Indian Council of Medical Research’s (ICMR) findings to say that the Zika strain — which had earlier caused an outbreak in Rajasthan — did not have “known mutations” for microcephaly. M.P.’s health officials are now waiting for the ICMR to genetically sequence the local Zika strain, as they believe it may also lack those mutations, and so, may not be dangerous to foetuses. Only if the strain turns out to have the dangerous genetic changes, health officials said, would they begin explicitly warning couples about delaying pregnancies during the outbreak. Pallavi Govil Jain, M.P.’s Health Commissioner, says: “Because we still don’t know from the Health Ministry whether the strain can cause microcephaly, we have to be cautious about what we tell women. If we tell them that it will impact their children, it will cause panic among the public.”

This delay in launching intensive communication campaigns can cost lives, according to Zika researchers, because all Zika strains can probably cause birth defects. Contrary to what the Health Ministry’s press release suggests, there is no “known mutation” for microcephaly. “People have got to stop saying this,”, says Nathan Grubaugh, an epidemiologist at the Yale School of Public Health. “It’s going to drive complacency within the general population if they don’t believe Zika can cause birth defects,” he adds. Grubaugh studied the Brazil and U.S. Zika epidemics, in 2015.

Anant Bhan, a Bhopal-based bioethics researcher, says the State government’s concern about causing alarm can be tackled with a good communications strategy. “Contextualise the communication, so that it is done sensitively. But not sharing or withholding information is not acceptable,” he says.

One reason why the State Health Department cannot drag its feet about informing people is that Zika epidemics are typically larger than they appear. Nearly 80% of the infected people do not show symptoms. Therefore, surveillance systems detect only a fraction of the cases. This means that even though diagnostic tests have so far uncovered not more than 127 cases with 35 pregnant women in M.P., the actual number could be many times as much. In such a situation, says Grubagh, telling women that Zika is linked to birth defects can motivate them to protect themselves, softening the impact of the virus. “If I were in such a situation, and if there was information that I could use to my benefit, I would want to know it. I don’t want people to tell me: Oh, it’s not an issue, when it actually is,” he adds.

India’s first major outbreaks

India’s first major Zika outbreak began in September 2018 in Rajasthan. Until then, a surveillance programme run by the ICMR at 35 sites across the country had detected only three isolated cases in Gujarat in 2016-17, and one in Tamil Nadu.

Ground Zero | Stopping the virus — muddled science, poor public health communication mar India’s response to Zika outbreak

Then, in September, the surveillance system, which randomly tests a fixed number of fever patients for Zika each month, found an 85-year old woman from Jaipur to be carrying the virus. Over the next few days, more and more cases turned up. Rajasthan then began testing all pregnant women living in a three-km radius around the index case. This effort uncovered a total of 154 cases, with over 60 pregnant women among them. Two of these women have given birth and the babies are healthy, officials say.

Around mid-November, State officials declared that their extensive larvicidal and fogging activities had “controlled” the outbreak. According to Govind Pareek, Deputy Director, Public Relations for the Government of Rajasthan, no new cases were found in the two weeks leading up to the announcement.

However, by this time, the ICMR’s surveillance system in Bhopal had picked up a second outbreak. As this story goes to print, M.P.’s officials say that there are 127 infections in six districts of the State. But according to B.N. Chouhan, the State’s Director of Health Services, the outbreak seems to be slowing down due to intensive mosquito-control activities.

Silent epidemics

Yet, there are several questions about whether the outbreaks in Rajasthan and M.P. have truly been extinguished. Zika cases typically rise and drop with the seasonal prevalence of the Aedes mosquito, which means the drop in November may have as much to do with the weather as with antilarval activity. Says Grubagh, “Control of an outbreak is quite hard to define. First, not detecting Zika cases doesn’t necessarily mean that transmission stopped, because the vast majority of cases are asymptomatic.”

Second, the ICMR’s surveillance system relies on a technique called Reverse Transcription-Polymerase Chain Reaction (RT-PCR), which looks for Zika’s genetic signature in patient blood samples. But RT-PCR tends to throw up false-negatives when there is too little virus in the patient’s blood, something that happens frequently with Zika, says Grubaugh. Such barriers mean that the best of surveillance systems catch only a fraction of the incidence. After an outbreak in Salvador, Brazil during 2015, researchers found that the number of people who had Zika antibodies — indicating that they had been infected in the past — was roughly 40 times the number of detected cases. If the same multiple is applied to MP, then, given its 127 detected cases, the potential number of infections could be as high as 5,080.

image/svg+xml Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug 0.0 0.1 0.2 0.3 0 40 80 120 160 Mosquito abundance Zika cases Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug 0.0 0.1 0.2 0.3 0 40 80 120 160 Mosquito abundance Zika cases