The number of patients with West Nile fever continues to climb, additional patients have been diagnosed throughout Gush Dan and senior officials in the health system warn of hundreds of cases of infection if immediate actions are not taken to eradicate mosquitoes. Here are some questions about fever and the answers to them.
When did the disease first appear in Israel?
According to data from the Ministry of Health, the disease has been widespread in Israel for many years and tends to appear in peak waves in the summer. The first documentation of West Nile fever as an outbreak was recorded in Israel in 1950-1954 and in 1957 a second outbreak was recorded.
In the 1970s and 1980s, increased activity of the virus was recorded again. In 1997, the disease was diagnosed in poultry, for the first time flocks of geese for fattening were affected, which were found to be particularly sensitive, and the disease manifested itself a year later in a large-scale outbreak. In 2000 there was an outbreak in Israel with more than 400 cases of the disease. From 2001 until today, dozens of cases have been diagnosed every year.
What is the infection rate in Israel?
Every year several dozen patients are reported in Israel, most of them in their fourth decade or older. The wave of morbidity this summer is very high and according to the forecast it will only get worse.
Which areas are infected in Israel?
The infected mosquitoes are mostly found in the areas of Sharon, Hadera, Pardes Hana-Karkur in Nimina and Caesarea. However, cases of infection have already been reported in the past throughout the country, from north to south. In the current case, the cases were recorded this month in North Tel Aviv, Ramat Gan, Givatayim, and the Savion area.
What are the symptoms of the disease?
This is a mild disease for the most part, but it can also cause severe morbidity and mortality. The infection usually passes without symptoms. In some cases, a flu-like illness appears which goes away on its own. Symptoms include fever, headache, weakness, joint and muscle pain, conjunctivitis, rash and sometimes nausea and diarrhea.
In about 1% of cases the disease becomes severe, with neurological signs corresponding to meningitis, acute encephalitis or acute flaccid paralysis. The incubation period is usually 5 to 21 days. The disease does not pass from person to person and there is no risk of infection by staying near a sick person.
What to do if you are bitten?
Most mosquitoes in Israel are not infected with the reagent and therefore there is no reason to panic. In the event of an allergic reaction to a bite manifested by swelling, redness and itching, or the appearance of signs of infection manifested by redness, local heat, pain or high fever, or in the event of the appearance of flu symptoms after a bite such as high fever, weakness, muscle pain, shortness of breath and vomiting, seek medical advice.
Is it possible to get infected from a person infected with a virus?
No, as is known, the disease does not pass from person to person.
Who is at risk of serious illness?
The risk of infection is very low. At high risk are patients with chronic diseases that suppress the immune system, cancer patients with poor immune systems, infants and the elderly.
Can dogs and cats be infected and contagious?
According to the medical literature, the virus is transmitted in nature only by infected mosquitoes, and there is no evidence to suggest infection from an animal to humans.
If I have been infected before, can I be infected again?
Infection with the virus does not immunize against it, and therefore even those who have previously been infected with the West Nile virus may become infected again.
Is there a vaccine against the virus?
A vaccine against West Nile fever exists only in horses.
How is the treatment carried out?
There is no specific treatment for West Nile fever, and as mentioned in most cases the disease goes away on its own within a few days to weeks. Treatment focuses on alleviating symptoms through rest, drinking plenty of fluids, antipyretics, and pain relievers. In severe cases where hospitalization is required, treatment is given with fluid infusion, administration of antibiotics to prevent secondary infections, and in severe cases also ventilation. There are trials in severe patients with cerebral and neurological complications of infusion of antibodies known as IVIG for five days.
How are bites prevented?
Since there is no treatment against the disease, the only way to deal with it is to prevent mosquito bites through the use of mosquito repellents, nets for the windows, the use of a fan that helps keep mosquitoes away and appropriate clothing. If you have located an area with a lot of mosquitoes, or a water reservoir, report it immediately to the local authority.