Jalisco health authorities have stepped up precautions at the Guadalajara and Puerto Vallarta airports following the worst outbreak of West Nile virus in the United States since 1999.
Almost 2,000 cases of the disease and 87 deaths have been reported north of the border, the Centers for Disease and Prevention (CDC) said in its latest press announcement on September 4.
The CDC said the disease has been reported in mosquitoes, birds or people in 48 states. Forty-three states have reported at least one human case. Over 70 percent of the cases have been reported from six states (Texas, South Dakota, Mississippi, Oklahoma, Louisiana, and Michigan) and over 45 percent of all cases have been reported from Texas.
According to Leandro Hernandez Barrios, infected mosquitoes have occasionally been identified at some dams and reservoirs in Jalisco and the last animal infection was in 2003. There has never been a registered case in humans, he said.
Airport personnel have been told to fumigate all planes arriving at the two airports from the United States. (More flights arrive from Texas than any other U.S. state.) Over the past three weeks health workers have carried out checks for infected mosquitoes or animals in four neighborhoods in close proximity to the Guadalajara airport.
In most cases, West Nile virus is spread by the bite of an infected mosquito.
According to the CDC, about one in 150 people infected with West Nile virus will develop severe illness. The symptoms can include high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness and paralysis. Up to 20 percent of people infected have mild symptoms that may last only a few days. Approximately 80 percent of people (about 4 out of 5) will not show any symptoms at all.
Symptoms usually develop between 3 and 14 days.