West Nile infection 66 death in US

One of the worst outbreaks of West Nile virus to ever hit the United States continues to expand, with 66 deaths and 1,590 illnesses reported, according to the US Centers for Disease Control and Prevention. Cases have jumped 40% nationwide since just last week, the agency added. Cases have now reached their highest level since the mosquito-borne virus was first found in the United States in 1999, agency officials said in press briefing. While almost all states have reported at least one case of West Nile illness, over 70% of cases have come from six states Texas, South Dakota, Mississippi, Oklahoma, Louisiana, and Michigan. The outbreak has hit hardest in Texas, where nearly half (45%) of the total US cases have been reported. “The number of people reported with West Nile virus continues to rise,” said Dr. Lyle Petersen, director of the CDC’s Division of Vector-Borne Infectious Diseases. “We have seen this trend in previous West Nile epidemics, so the increase is not unexpected,” he added. “In fact, we think the reported numbers will get higher through October.” According to Peterson, of the cases reported so far, 56 percent are what is called neuroinvasive disease, when the virus enters the nervous system causing conditions such as meningitis or encephalitis. The remaining reported cases (44%) are non-neuroinvasive. “These numbers represent a 40% increase of last week’s report of 1,118 total cases and 41 deaths,” Petersen said. These numbers can be somewhat misleading since most cases of West Nile are non-neuroinvasive and are mostly unreported, the CDC said. That means that the number of unreported cases probably far exceeds reported ones. Neuroinvasive disease is the most serious for of West Nile infection and these patients usually are hospitalized, Petersen said. The size of the outbreak is based on these cases since they are the ones easily identifiable, he added. The only states that have not reported cases are Alaska and Hawaii, he said. “Based on current reports, we think the number of cases may come close to, or even exceed, the total number reported in the epidemic years of 2002 and 2003, when more than 3,000 cases of neuroinvasive disease and more than 260 deaths were reported each year,” Petersen said. According to World Health Organization (WHO) West Nile Virus (WNV) was first isolated in a woman in the West Nile district of Uganda in 1937. It was identified in birds (crows and columbiformes) in Nile delta region in 1953. Before 1997 WNV was not considered pathogenic for birds, but at that time in Israel a more virulent strain caused the death of different bird species presenting signs of encephalitis and paralysis. Human infections attributable to WNV have been reported in many countries in the World for over 50 years.