This year, Uttar Pradesh has reported 1,069 dengue cases to the National Vector Borne Disease Control Programme, the central government’s nodal agency on vector borne diseases. However, it has not reported a single death caused by dengue, data from the agency’s regional office shows.

This, despite the fact that more than 50 people have died of fever in the past one month in just one district, Firozabad, which is currently seeing a dengue outbreak. The district has 300 confirmed cases of the viral disease.

Officials say they suspect at least 100 people have died of dengue across the state. They attributed the gap between the official number – zero dengue deaths – and the actual situation on the ground to poor disease surveillance in Uttar Pradesh.

Only those patients who were tested and confirmed to be infected with dengue before they died are officially counted as dengue deaths. Even then, districts hold a death audit meeting to assess whether dengue was the cause of death.

At least two officials of the National Vector Borne Disease Control Programme told that they suspect Uttar Pradesh is underreporting its dengue cases due to limited testing.

In the absence of testing, state officials said they planned to conduct a death audit through verbal autopsies to establish the cause of death. “Until a death audit is carried out, none of these deaths can be confirmed [as being] due to dengue,” said Amit Mohan Prasad, principal secretary of health in Uttar Pradesh.

Dr Vikas Singhal, joint director of the state’s vector borne disease unit, explained: “Most deaths have occurred outside the hospital. For those who died before hospitalisation, districts will have to take a detailed medical history before they can be labelled as dengue deaths.”

For now, these deaths are being put down to viral fever, said Dr Umesh Tripathi, chief medical officer in Etah, a district neighbouring Firozabad, which is also reporting a high number of cases.

A five-member team of the National Centre for Disease Control visited Firozabad district last week to assess the situation. “We have given an indication to the state government that there is a rise in dengue cases for sure, and Firozabad is the epicentre,” said Dr Himanshu Chauhan, joint director of the Integrated Disease Surveillance Programme run by the National Centre for Disease Control. “Our job is surveillance and not control. Reporting of cases is by the state government.”

An erratic curve

Data available on the website of the National Vector Borne Disease Control Programme shows Uttar Pradesh’s reporting of dengue cases has been erratic over the years.

In 2016, the state reported 15,033 dengue cases. This dropped to 3,092 in 2017 and 3,829 in 2018. There were 28 dengue deaths in 2017 and only four in 2018.

In 2019, the numbers shot up to 10,557 cases with 26 deaths. Then in 2020 they fell back to 3,715 and just six deaths.

On the website, the data available for this year is only till the month of July – it reflects just 160 dengue cases in Uttar Pradesh.

“It is possible that the pattern of infection changes every year,” said a former official of the National Vector Borne Disease Control Programme who lives in Delhi. “But it is also possible that there is underreporting in the last two years and enough tests were not undertaken.”

The official added that since all health workers were roped into Covid-19 duty from 2020, it was likely that regular disease surveillance had taken a hit.

Delays in testing and reporting

This year, most suspected dengue deaths occurred before patients could be hospitalised, indicating a delay in testing and treatment.

Take the case of Koh, a village in Mathura district, where a huge cluster of dengue and scrub typhus cases has been recorded over the last one month. In a village of less than 2,000 people, at least 12 had reportedly died of “fever” in the three months up to September 6, said Thakur Anil Singh, block president of the Bharatiya Janata Party in Koh.

“Of these 12 deaths, 10 were children,” Singh added. “They all had high fever. We do not know how many were due to dengue or scrub typhus.” Scrub typhus is a bacterial disease that spreads to people through bites of chiggers, or larval mites.

“A few of the children died before hospitalisation so no tests could be carried out,” Singh said. “When the situation worsened we started getting children admitted to hospitals. The survey to detect mosquito larvae began a few days ago and several breeding sites were found in the village.”

Dengue is commonly tested through two methods in India. IgM (immunoglobulin M) kits for ELISA (enzyme linked immunosorbent assay) are considered the most accurate to confirm dengue infection. ELISA detects antibodies, developed within seven to 10 of infection, against the virus. The second way is to conduct an NS1 (non-structural glycoprotein 1) antigen rapid test to detect proteins of the virus. This has faster turnaround time, but it also has high chances of returning a false positive or false negative report.

“Even a positive result could mean it is not a dengue infection,” said Dr Sher Singh Kashyotia, public health expert who formerly handled vector borne diseases at the National Vector Borne Diseases Control Programme. “It could be any infection from the arboviral group. That is why in India only ELISA is considered final confirmation for dengue,”

A single IgM kit can be used to carry out 96 tests. Despite a large population, Uttar Pradesh’s demand for IgM kits to test dengue remains low. In 2021, the National Vector Borne Diseases Control Programme allocated 460 IgM kits to Uttar Pradesh out of the 7,000 kits meant for India.

A senior officer in the programme said allocation is based on the demand made by each state. Maharashtra, Kerala, Karnataka, Delhi, Gujarat and Tamil Nadu have received over 500 kits. With dengue cases rising, Uttar Pradesh recently placed a new request for more kits from the centre, he said.

“One factor for higher kit allocation is higher reporting plus higher prevalence of infection in states like Maharashtra, Tamil Nadu and Kerala. But it is also possible that UP is carrying out fewer tests and detecting less cases,” the official said.

Singhal, joint director of the state’s vector borne diseases unit, insisted they were complying with testing norms. “If there is a dengue outbreak in an area, we treat fever cases from that area as dengue and begin symptomatic treatment accordingly,” he said. “Testing every case is not necessary. But we are still trying to test all cases.”

A woman pleads with a doctor to treat her unconscious son in Firozabad. Photo credit: Alok Pandey/ Twitter

A personnel crunch?

It is not that the state lacks infrastructure to monitor for the disease. India had 707 sentinel surveillance hospitals, meant to record information about dengue cases in a particular region. Uttar Pradesh has 54, the highest number in the country. It is also home to two of the country’s 17 apex referral laboratories for confirmatory tests: King George Medical University and Sanjay Gandhi Postgraduate Institute of Medical Sciences in Lucknow.

Officials in the state and central government said Uttar Pradesh lacked the manpower to detect and report dengue cases in time.

Accredited Social Health Activists could help in early detection through rapid antigen kits, which could work as a mass surveillance tool despite low sensitivity rates. In Maharashtra, ASHA workers are trained to inspect water for mosquito breeding sites, take blood samples and use rapid test kits. Such training has not been given to ASHA workers in Uttar Pradesh.

In Etawah, adjoining Firozabad district, ASHA block facilitator Meera Yadav Basrehar said they had only been asked to carry out door-to-door surveys to find patients suffering from fever. “We give the name and address of suspected cases to the local authority,” she said. “At our level, we carry out no testing. We don’t receive kits for rapid tests.”

The Firozabad hotspot

Over the last few years, Lucknow, followed by Kanpur, reported the most dengue cases in Uttar Pradesh. But with over 50 suspected deaths due to “dengue-like fever”, Firozabad seems to be the epicentre for the disease this year.

Data from district officials show Firozabad has recorded over 300 dengue cases so far, up from one case in 2017, zero in 2018, 21 in 2019 and one in 2020.

“This is the first time in the last three years that Firozabad is recording high load of dengue infection,” said Singhal, head of the state’s vector borne disease unit.

In Mathura, 113 dengue cases have been confirmed. “We are finding a clustering of cases in these two districts,” Singhal said. “Entire families are testing positive, which means mosquito breeding is happening within the neighbourhood.”

He attributed the sudden rise in cases to weather conditions: “There is over 80% humidity, a very conducive environment for mosquitoes to breed at this point.”

Dr Shaukat Kamal, deputy director of the National Vector Borne Disease Control Programme in Uttar Pradesh, said the state had seen intermittent rains interspersed with dry spells that continued for three to four days. “The hot and humid climate is most apt for mosquito breeding,” he said.

Officials making inspection rounds had found breeding spots in coolers, refrigerator plates, rooftops and storage tanks, said Dr VK Chaudhary, regional director of the National Vector Borne Disease Control Programme.

Officials said they are yet to isolate the virus to understand its serotype. There are four serotypes, or variations, of the virus: Den-I and Den-III are virulent and can cause more severe infections than the Den-2 and Den-4 serotypes.

While dengue is suspected to be the cause of the recent spate of deaths in Firozabad, other infectious diseases are also spreading in the region. Over the last few days, 52 samples taken from persons suffering from fever were tested in Firozabad. Of these, 22 were positive for scrub typhus and four for leptospirosis, a bacterial disease. In Mathura district, 48 cases of leptospirosis were found in a single village. Two other villages accounted for 29 cases of scrub typhus. In Prayagraj, cases of encephalitis and pneumonia are also rising among children.

This reporting was supported by a grant from the Thakur Family Foundation. Thakur Family Foundation has not exercised any editorial control over the contents of this article.