Infectious disease specialist Andreoni says there are numerous West Nile cases, but be alert for the silent ones.

"West Nile fever is a disease that should not be underestimated. The problem is that known cases are still a minority compared to the 'hidden' cases that are certainly detectable in the affected areas. In fact, the infection rate is one symptomatic case for every 5-10 asymptomatic cases," Massimo Andreoni, infectious disease specialist and scientific director of the Society of Infectious and Tropical Diseases, explained to ANSA after the death of a woman in Latina. This means, he notes, that "to have a precise estimate of how much the infection is circulating, we should also test apparently healthy individuals in the affected areas, to understand how many people are actually infected." West Nile fever "can be a highly pathogenic disease with a serious neuroinvasive profile in cases where the infection spreads to the central nervous system, affecting the brain or spinal cord; but even when it is not neuroinvasive," the expert specifies, "West Nile can be a serious disease if it affects the elderly or frail, as it can worsen their pre-existing general conditions, being a systemic disease." According to Andreoni, "the number of asymptomatic infected people is presumably larger than previously thought, and if there are so many infected people, this means there is widespread circulation of transmitting mosquitoes, most often infected by sick birds or equines. It is, in fact, rarer for a mosquito to contract the virus from a human and transmit it to another human." Obviously, the more infected people there are, he warns, "the higher the percentage of serious cases that can occur out of the total, which we should expect in the coming days, considering that the incubation period for the disease is 7-10 days." Therefore, "Being able to know the true number of infected individuals in the area allows us to paint a clearer epidemiological picture and would allow us to predict the number of more serious cases we could expect in the short term." At the moment, the infectious disease specialist concludes, "the most urgent measure is to disinfect the affected areas to eradicate the mosquitoes carrying the virus, but we need to see how the infection progresses to determine what measures to take: whether they will be aimed solely at disinfection or will also involve more thorough epidemiological tests on humans."