Mrs. X. brought her four-year-old daughter to the office because of a fever and cough. She said that her daughter was cranky and “just not herself”. It didn’t take long to find out that she had a raging ear infection. I assured mom that the child would be fine after she was started on antibiotics. However, I could sense that something else was bothering
Mrs. X. When asked she admitted having watched one of the news programs recently and was shown a special on West Nile Virus, WNV. Her daughter had been bitten by mosquitoes the week before, and mom wanted reassurance that she didn’t have the deadly virus.
The public has been inundated with coverage of the WNV over the past few weeks, both in print media and over the airways. What is West Nile Virus? When did it get here, and what should be done about it?
The first case of WNV in the United States occurred in New York City on August 12, 1999. A 60-year-old man was admitted to Flushing Hospital Medical Center with a three-day history of fever, weakness and nausea. He was initially thought to have a pneumonia and was treated with antibiotics. However, his condition deteriorated, and within four days he was disoriented, confused, experienced loss of bladder control and had respiratory difficulties. In the intensive care unit it was thought that he had encephalitis. Now he underwent aggressive, life-saving measures, and after a six-week stay in the ICU, he was discharged as improved, but not back to normal. Within a two-week period there were four more similar cases admitted to New York City hospitals--older people, 80,75,87 and 59 years, all thought to have encephalitis. This prompted the Department of Health to get involved. As their investigation was starting three more cases were reported, making the total number of eight.
The NYCDOH, Department of Health, identified these eight patients as being active and previously in relatively good health. Their ages ranged from 58 to 87 years, and they lived within a four-mile radius of each other in Queens. All had fever and intestinal symptoms that were followed by changes in levels of consciousness, muscle weakness and paralysis. All had given a history of spending time outdoors in the evening hours during the two weeks before becoming ill. The labs suggested that the cause of their illness was a virus.
In September of that year, it was believed that they all had St. Louis encephalitis, SLE, a mosquito borne viral infection that could cause the symptoms these patients were experiencing. SLE had already been reported in the state of New York, but never in the city. Nonetheless, a $14 million effort was launched at mosquito control. This included both ground and aerial spraying. A telephone hot line was set up and handled over 150,000 calls. Over 400,000 cans of mosquito repellent were distributed by firehouses. This effort covered an area of four counties.
At this same time it was noted that an increasingly large number of birds were dying. In June a veterinarian in Queens took notice of a number of birds that he had seen with nervous system disorders. Several exotic birds at the Bronx Zoo had died unexpectedly and it was felt that they had succumbed to the SLE that had affected the eight humans. The chief pathologist at the zoo was perplexed, as the SLE virus does not usually make the host, the birds, sick. Samples were sent to the U.S. Department of Agriculture’s National Veterinary Service, the U.S. Army Medical Research Institute of Infectious Diseases, and the Center for Disease Control. The CDC confirmed on September 23, that the birds had died from WNV.
Simultaneously, tissue samples from three of the initial eight patients were sent to the University of California at Irvine. It was determined that these patients, too, had WNV. On September 27th the CDC confirmed the first documented cases of WNV in the Western Hemisphere.
WNV is a virus that is spread by a mosquito and the main reservoir is wild birds. It was first isolated in 1937 in the blood of a febrile Ugandan woman who was otherwise without symptoms. WNV is found in Africa, the Middle East and parts of Russia, India and Indonesia. The incubation period is 5 to 15 days. The majority of infections are clinically silent; in fact, the majority of people that become infected have no symptoms at all. Those who do develop symptoms may show fever, headache, muscle aches, sore throat, conjunctivitis, and diarrhea. Close to 50 percent of patients with WNV will have a rash on the trunk and arms. Many patients will have swollen lymph nodes, but these do not occur in any particular distribution. It is estimated that serious illness from West Nile Virus occurs in around 1 out of 150 cases, much less than one percent. These symptoms would include high fever, stiff neck, coma, convulsions, weakness and paralysis. The elderly are at particular risk for developing serious disease. There is no specific treatment for WNV other than supportive care. Studies are underway to try to develop a vaccine.
A recent case report out of Michigan found that a mom developed West Nile Virus through a blood transfusion during childbirth. She had planned to breast feed even though the lab tests showed that the virus was present in her milk. She continued to breast feed, and after three weeks her newborn tested positive for the virus. Up until now both mom and baby are doing fine.
With the outbreak in New York City in 1999, the ArboNET Surveillance Program was conceived. This is a multi-disciplinary task force whose main objective is to collect data and monitor the spread of WNV in the United States. They set up strategies to prevent human or animal infection once an outbreak has been suspected. ArboNET now has 54 state and local health departments that cover the 48 contiguous states. As recent news accounts report, the WNV had steadily moved westward. There are many challenges facing the health community. It is well known that climate and weather greatly affect the mosquito population. Extremely hot temperatures are not only favorable to the mosquito, but also speeds the growth of the virus in the mosquito. This is one variable man has no control over. But with increased public awareness, vigilance on the part of monitoring agencies, strong collaboration between public health agencies, community physicians and veterinarians, the task will be met.