© David Zalubowski/APIllustrative: Mosquitoes cling to the inside of a jar loaded with repellent during a test as part of a tour of the Centers for Disease Control laboratory, April 4, 2024, in Fort Collins, Colorado.
Seven people recently hospitalized in the Tel Aviv area were found to be infected with West Nile fever, a disease spread by mosquitos that can be fatal.

Five of the patients were treated at the Ichilov Hospital in Tel Aviv and were apparently infected in northern areas of the city, according to Hebrew media reports on Monday. Two are still in serious condition.

Channel 12 reported that another two patients were recently hospitalized at the Sheba Medical Center, in Ramat Gan near Tel Aviv, but have since been discharged.

While a doctor at Ichilov warned that the number of cases appears to be spiking, the Health Ministry and the Environmental Protection Ministry said they had not identified an outbreak but were monitoring the situation.

Those infected with West Nile virus typically experience flu-like symptoms and recover within a week, but in some cases the disease is fatal.

Dr. Yevgeni Katzman, an expert in internal medicine and infectious diseases at Ichilov, told Channel 12 that there are three people still hospitalized at the medical center with the disease, two of them in serious condition. Two further patients recently at the hospital also tested positive for the disease.

"This is an outbreak so it is important to alert and warn the public," he said. "In all my years as a doctor, I have never seen so many patients arriving so close together to be hospitalized because of the disease."

He said the hospital would typically see one case, or two at worst, each year.

Diagnosis is through serological tests and Katzman estimated that if Ichilov has already had five patients, there could be "dozens" more who have not been diagnosed.

There is no vaccine or effective drug against the disease, which Katzman described as "frustrating" to doctors.

He noted that the disease is mostly dangerous for the elderly, while younger people are able to fight off the ailment with little more than "slight abdominal pain, diarrhea, or fever."

In older people it can develop into more serious or even fatal symptoms.

One of the patients was a "completely healthy" 77-year-old man who would walk five kilometers a day, Katzman said, but as a result of the disease he is "a shadow of his former self."

A 60-year-old had double vision and a brain injury from the disease, causing him slow reactions and difficulties in maintaining his balance.

A third patient, 79, had been planning to travel abroad with his wife when he felt feverish, and then his legs became so weak he could not stand, Katzman said. Tests found he had damage to his spinal cord.

"He was completely confused when he came to us and at one point he could not be woken up," Katzman said.

Shiri, whose father is hospitalized in Ichilov with the disease, called on authorities to do more to keep the public informed.

"They know but what are they doing about it?" she told the Ynet news outlet, urging the Tel Aviv municipality to begin spraying against mosquitos.

The Environmental Protection Ministry, which deals with fever outbreaks by countering mosquito breeding, said in a statement that despite the reports of hospitalized patients, "So far no mosquitos infected with West Nile Fever have been caught in the Tel Aviv area."

The Tel Aviv municipality must monitor the mosquito situation and "treat the hazard," said the ministry's head of pest control Shay Reicher in the statement, noting that city hall complied by carrying out patrols in areas suspected of harboring infected mosquitoes. A number of areas where standing water containing mosquito larvae were found were and dried up.

"At this stage, no additional patients with the disease have been reported," the ministry said.

The Health Ministry said in a statement that "at this stage there is no unusual morbidity trend in West Nile fever in Israel" and that it was monitoring the situation.

The ministry recommended to the public to use mosquito repellents and other measures to protect against contact with the insect.

Health Ministry figures show that from January to June last year there were six cases of West Nile Fever detected in Israel. During the same period in 2022, there were two, and in 2021 there were five. An outbreak in 2018 saw an outbreak of dozens of cases.