For more than a week now, children in some parts of the northern Indian state of Uttar Pradesh have been waking up with a high fever and sweating.

Many of them complained of joint pain, headache, dehydration and nausea, and some reported a rash on the legs and arms.

About 50 people, most of them children, have died so far due to fever, and hundreds have been taken to hospitals in six districts in the eastern region of the state, and none of the deceased has tested positive for COVID-19.

At a time when India appears to be slowly recovering from a second wave that kills citizens due to infection with the Corona virus, the deaths in the state of Uttar Pradesh made headlines about the presence of a “mysterious fever” sweeping the countryside of the most populous state in India.

Doctors in a few of the affected areas, namely Agra, Mathura, Mainburi, Ita, Kasjang and Firuzabad, believe that dengue fever, which arises from a viral infection transmitted by mosquitoes, may be the main cause of these infections and deaths.

They say many patients have been hospitalized because of a drop in the number of platelets, a component of blood that helps form clots, which characterizes an acute form of dengue fever.

“Patients, especially children, are dying in hospitals very quickly,” says Nita Kulcherista, the top health official in Firozabad district, where 40 people, including 32 children, died last week.

Dengue fever, which is transmitted by female mosquitoes, is a tropical disease that has been circulating in India for hundreds of years, and is considered a pandemic in more than 100 countries, but 70 percent of cases are reported in Asia.

There are four viruses that cause dengue fever, and children are five times more likely to die than adults if they become infected.

The Aedes aegypti mosquito breeds in and around homes in containers containing fresh water.

“Humans prepare mosquito breeding grounds, and only humans can get rid of them,” says Scott Halstead, one of the world’s leading experts on viruses spread by mosquitoes.

About 100 million severe cases of dengue, with severe bleeding and organ damage, are reported worldwide each year.

The World Health Organization says that “the combined effect of COVID-19 and the dengue epidemic may lead to severe consequences for vulnerable populations.”

However, it remains unclear if the dengue epidemic is solely responsible for the fever-related deaths in Uttar Pradesh.

The state of more than 200 million people, which suffers from poor sanitation standards, high levels of child malnutrition and poor healthcare, consistently reports cases of this “mysterious fever” after the monsoon rains every two years.

The infection of Japanese encephalitis, also transmitted by mosquitoes, which was first detected in Uttar Pradesh in 1978, has killed more than 6,500 people since that time, and the disease has spread mainly in Gorakhpur district and neighboring areas bordering Nepal in the foothills of the mountains The Himalayas, all of which are lowland and prone to flooding, also provide a breeding ground for the mosquitoes that transmit the virus.

A vaccination campaign, which began in 2013, led to a decline in cases, but children are dying so far. 17 children died of Japanese encephalitis in Gorakhpur this year, and 428 cases were recorded.

Scientists had examined 250 infected children in Gorakhpur in 2014, in response to an increase in child deaths due to encephalitis and myocarditis, and scientists detected in 160 children antibodies to the bacteria that cause scrub typhus.

Scrub typhus, also known as bush typhus, is a bacterial infection spread by the bites of a virus-infected moth.

The moth settles on the vegetation spread in the villages after the seasonal rains, and scientists have also monitored the presence of the moth on the wood that the villagers store inside their homes. .

In an independent study, scientists also concluded that typhus and dengue fever were linked to cases of post-monsoon fever in six districts in eastern Uttar Pradesh between 2015 and 2019, as well as another deadly bacterial infection called animal-transmitted leptospirosis. to humans, and chikungunya, a mosquito-borne disease that causes other disease-transmitting fevers.

“There is a cluster of fever-related illnesses that hit the region after the monsoons are over,” says V. Ravi, professor of virology at the National Institute of Mental Health and Neuroscience, who led the second study. You need systematic monitoring to track and treat these diseases.”

Earlier in 2006, scientists investigated another “mystery” outbreak causing fever-related deaths among children in Uttar Pradesh, this time concluding that the children died after eating cassia beans, which were widely grown in the western region of the state.

The scientists concluded that this food poisoning was due to “poverty, hunger, lack of parental supervision, ignorance, children playing alone, lack of toys and easy access to plants.”

It is clear that only further studies and analysis of the genome will reveal whether the recent wave of “mysterious fever” in India was caused by dengue fever alone, or from a group of other diseases, and this means training local clinics and hospitals to collect samples from people suffering from dengue. Fever and sent to laboratories for genome examination.

There is also no clear record of how this fever started and how it developed, and whether the acute infection might have been caused by the long and arduous journeys people had to make to get to government hospitals for treatment, or if infected children had other illnesses such as tuberculosis.

If the mysterious deaths were due to dengue fever alone, then this indicates ineffective government mosquito control programmes.

The severity of transmission can only be determined by antibody tests, called serological surveys, according to age groups, Halstead says.

“If we don’t investigate properly and regularly, a lot of things will remain a mystery,” said an Indian virologist, who did not give his name.

BBC Arabic