West Nile virus infects humans when they are bitten by an infected mosquito or through blood transfusion or organ donation. But, we should also still be careful of the things around us, like for instance, the food we eat.
WNV infection risks from eating an infected game animal
According to the CDC there is no evidence that people will be infected by the West Nile Virus if they eat infected meat.
However, food, especially game meat should be handled and cooked properly because several food-borne diseases can be gotten from eating uncooked, undercooked or improperly handled meat.
WNV infection risks from eating dried uncooked meat
As of now, studies are yet to be published on this issue. Most studies report that although mammals can get infected by the virus, they do not develop high concentrations of the virus in their blood or tissues.
Though it is nearly impossible that dried mammal meat will retain much WNV virus and is likely that gastrointestinal digestion would further diminish the risks, the fact is that there is still very little evidence to determine if dried meat is presents a risk of WNV infection to humans (or other animals).
WNV risk for game hunters
Game hunters may be more at risk of being bitten by mosquitoes because they are exposed to the outdoors.
To protect themselves from being infected, they should exercise proper care and use the necessary precautions when handling wild animals. They should also apply insect repellent both to skin and clothing to prevent mosquito bites. Use protective clothing when handling and cleaning animals, such as gloves to prevent blood exposure.
There have been 114 reports of Human West Nile Virus Infection.
Of the 114 human cases of West Nile Virus Infection
45 of them suffered from Encephalitis and Meningitis.
67 had fever.
2 had unspecified conditions.
There have been 2 fatalities.
Affected States include:
Alabama, Arizona, Arkansas, California, Colorado, Connecticut, Idaho, Louisiana, Minnesota, Mississippi, Missouri, Nebraska, Nevada, North Dakota, Ohio, Oklahoma, Pennsylvania, South Dakota, Tennessee, Texas, Utah, West Virginia, and Wyoming.
17 presumptively viremic blood donors have been reported to the Center for Diseases Control and Prevention
Affected States include:
Arizona, California, Iowa, Kentucky and Louisiana.
Animal, Bird or Mosquito infections have also been reported from the following states:
Alabama, Arkansas, Arizona, California, Colorado, Connecticut, Florida, Iowa, Idaho, Illinois, Indiana, Louisiana, Massachusetts, Minnesota, Missouri, Mississippi, North Carolina, North Dakota, Nebraska, New Jersey, Nevada, New York, Ohio, Oklahoma, Pennsylvania, Puerto Rico, South Carolina, South Dakota, Tennessee, Texas, Utah, Virginia, Washington, Wisconsin, and West Virginia.
*From CDC West Nile Virus Activity Maps and Statistics
In 2002, there was a case of transplacental (mother-to-child) transmission of the West Nile Virus reported. However, due to the limited number of cases reported, it is still impossible to tell what risks infections during pregnancy pose to the unborn child.
West Nile Virus and Pregnancy
The 2002 reported case of transplacental transmission of the West Nile virus resulted in the child having the West Nile virus infection at birth, as well as severe medical problems. However, according to Centers For Disease Control and Prevention (CDC), it cannot be said for certain whether these problems were caused by West Nile Virus Infection or were due to other causes. The CDC and local health departments started a registry to monitor birth outcomes among women with West Nile virus illness in pregnancy.
In the same year, there were three other expectant mothers who were infected by the West Nile Virus were tested and analyzed. None of these resulted in the infants having the infection at birth. There was one more case of a pregnant mother infected with the virus, but it there was no way to tell whether this resulted in tranplacental transmission of the virus because the testing was incomplete.
From 2003-2004, there were 77 expectant women identified by the registry who acquired the West Nile Virus Infection. The results were: 71 delivered live infants. 2 had elective abortions and 4 miscarried in the first trimester.
West Nile Virus and Breastfeeding
In 2002, there was a reported case in Michigan where a mother contracted the West Nile Virus from a blood transfusion not long after giving birth. Her child was healthy. She breastfed her child, but 3 weeks later, the baby’s blood tested positive for West Nile Virus. Laboratory tests showed evidence of West Nile Virus her breast milk. Due to the child’s minimal exposure outdoors, it is unlikely that the infection came from a mosquito.
Protection from West Nile Virus
It is safe for women to use mosquito repellents to keep mosquitoes away. There have been no reports of adverse effects following the use of repellents (containing DEET or picaridin) in pregnant or breastfeeding women.
For breastfeeding women who are symptomatic for West Nile virus or are living in an area of West Nile virus transmission, the CDC says: Because the health benefits of breastfeeding are well established, and the risk for West Nile virus transmission through breastfeeding is unknown, the new findings do not suggest a change in breastfeeding recommendations.
Of course if you are lactating and are sick or having trouble breastfeeding, consult your doctor immediately.
All of us go to our health care provider when we feel something. In this case, if a person has symptoms of a West Nile virus illness, a specimen is sent of a commercial lab to determine if the person really has been infected by the virus.
Commercial lab tests check for antibodies to the virus. The test results will be sent to your doctor and the state health department will be informed, once the results are confirmed positive.
Though the WNV infection has no cure and though the diagnosis does not change the way the person infected with the virus is being treated, it informs your doctor that he/she does not have to investigate another cause of sickness. Also, it helps your state health department know which areas the virus is active in. Thus, they can plan preventive measures properly. The state health department either will accept that lab test results or test the sample again in the state health department lab to confirm the presence of the infection.
Accuracy of the tests used in commercial labs
Tests used in commercial labs are patterned after tests created and used at the CDC and in state health labs. There will most likely be a second test done on the sample to confirm the infection. State health departments, the FDA, the Association of Public Health Laboratories and CDC are all engaged in tracking new commercial tests. They are also committed to working with the industry to make the tests as accurate as possible.
What does "false positive" test mean?
A "false positive" test result means that in the initial tests, it is indicated that a person has a West Nile Virus Infection. But later, after a more specific test has been done, the person is not actually infected. Naturally, it is important that the state health department and CDC get an accurate idea as to where people are contracting the virus so they can properly plan preventive measures. However, the result does not have a great impact on the individual. Again, there is no specific cure for WNV infection. The person may seek the help of a physician to see in another cause of the illness has to be indentified.
Humans are infected by the West Nile virus if they are bitten by an infected mosquito.
In the workplace, humans are usually protected from infected mosquitoes because offices and establishments are usually enclosed and air conditioned. However, there are still workers who are exposed to infected mosquitoes, and therefore their chances of contracting the virus are high.
Outdoor workers such as farmers, foresters, landscapers, groundskeepers and gardeners, painters, roofers, pavers, construction workers, laborers, mechanics, and others are at exposed to, and therefore, are at risk of contracting the virus.
Researchers such as entomologists and other field workers are also at risk from being bitten while conducting surveillance and other studies outdoors. The risk of WNV infection in the workplace is not limited to workers who perform their duties outdoors.
People who work in laboratories and clinical workers who perform necropsies of infected birds or handle infected tissues or fluids are also at risk from contracting WNV infections if their skin is cut and the WNV infected substance gets into the wound.
To prevent, or at least, lower the risks of being infected by the West Nile Virus in the workplace, employees should receive trainings and guidelines that describe and the potential risks exposure and infection.
Timely reporting of illnesses which is suspected to have been contracted from the workplace should be emphasized. Lastly, there should be a medical surveillance system in place in the work area to monitor and report WNV-like infection symptoms, laboratory incidents and/or accidents which involve possible exposure to the virus, as well as employee attendance.
As of July 8, 2008, the Centers for Disease Control and Prevention (CDC) has received reports of a total of 5 presumptively viremic blood donors (PVDs) through its ArboNET surveillance program through state and local health departments
A presumptively viremic blood donor is a person whose blood tested positive when screened for the presence of West Nile virus. PVDs are followed up by the blood agency to verify their infection with additional tests. Some PVDs do go on to develop symptoms after donation, at which point they would be included in the count of human disease cases by their state.
These cases were reported from three states namely California, Kentucky and Louisiana.
Some facts about PVD
Agencies which regulate transplant and blood issues
The US Health Resources and Services Administration (HRSA) and Centers for Medicare and Medicaid Services (CMS) have oversight over organ procurement and transplantation, while the Food and Drug Administration (FDA) regulates tissue and blood.
Current protocol for testing donors or organs before a transplant is conducted
Organ donors are screened to identify infectious risks on the basis of national organ-procurement standards. Screening of all organ donors with WNV NAT is not currently required or routinely performed due to:
The length of turnaround time to obtain WNV NAT testing, and
The unproven test performance in the organ-donation setting. National guidelines for organ-donor screening are continuously reevaluated by the Health Resources and Services Administration in consultation with FDA, CDC, and organ-procurement organizations.
The system of testing donated blood for WNV by nucleic acid-amplification test (NAT) has markedly reduced the risk of transfusion transmission.
Reuters reports on Thursday that that a new strain of the West Nile Virus is spreading better and earlier across the country. This new strain may thrive on hot American Summers.
According to a second team of researchers, a new strain has already completely overtaken the original strain. This new West Nile Virus strain is reportedly better suited to hotter weather. This means that outbreaks may worsen up north.
According to Lyle Petersen who helps lead the West Nile surveillance at the CDC, this also means that the outbreak will be worse in North America Compared to any part of the world.
The West Nile Virus was first introduced to the U.S. in 1999. It was during a particularly hot summer in New York City.
Compared to the rest of the world, the pattern of the outbreak in the U.S. is quite unusual. In a phone interview, Petersen said "In Europe, Africa and West Asia, where the virus was previously endemic, you’d see these big outbreaks and then they’d kind of disappear and then not come back for years on end. What we have seen in the United States, we’ve had repeated outbreaks every single year since 2002 — in fact, big outbreaks. This is an unusual pattern that not been seen before."
Petersen and Marm Kilpatrick of the Consortium for Conservation Medicine and the University of California Santa Cruz may have found the culprit – Hot American Summers.
The New West Nile Virus Strain
In their writing in the Public Library of Science journal PLoS Pathogens earlier this week, Kilpatrick and colleagues said they showed the new strain, first seen in 2002, replicates faster inside the bodies of mosquitoes when it’s warm.
In a phone interview, Kilpatrick said "The warmer the temperature, the faster it replicates in mosquitoes and the faster the mosquito can transmit the virus. "It also indicates that increases in temperatures due to global climate change would have major effects on transmission of the virus."
Petersen and Kilpatrick said it is known that mosquitoes transmit other diseases faster when it’s warm. And in their lab work, Kilpatrick and his colleagues showed that the 2002 strain of the West Nile Virus, does particularly well in warmer temperatures.
"The new strain appears to have evolved naturally," said Petersen. "We can no longer find the 1999 strain. It’s pretty dramatic," he said.
He also added that Kilpatrick’s findings fit in with what the CDC has seen. "What we observed is, at least in temperate climates, these big West Nile Virus outbreaks tend to occur in heat waves" said Petersen. However, he admits that it’s to soon to tell if there are any links between climate change and West Nile Virus.
Kilpatrick shares his findings, "If it gets too warm, mosquitoes die sooner, before they can spread the infection". He believes that in southern states, the new strain may not have an advantage since the temperatures would be too high. But in northern states and Canada, hot summers could make a big difference.
"It is probably going to push the northern boundary farther north," Kilpatrick predicts.
West Nile Virus is can cause serious illnesses that affect the central nervous system. The virus in now known throughout the United States. And we all know that the most possible way for a person to become infected is if he/she is bitten by an infected mosquito.
Transplant Recipients
According to reports, people who received transplants may be at a significantly higher risk of developing serious west nile virus diseases, including meningitis and encephalitis.
Increased Risk of Severe West Nile Virus Disease
The reason behind this is that medicines taken by transplant recipients can make it hard to fight infections. Making transplant recipients more likely to develop the severe forms of west nile virus disease, which includes meningitis, encephalitis, even death, more often than people with normal immune systems.
Special Considerations for Transplant Recipients
If a transplant recipient has an unexpected fever and/or neurological symptoms during mosquito season, west nile virus disease should be considered. This includes recipients who develop the infection long after they received their transplants.
Contact your health care provider if you suspect that you have symptoms of west nile virus infection.
Lastly, immunosuppressed recipients may have longer incubation period than a person with normal immune systems. Immunosuppressed recipients may also have delayed development of antibodies.
In Vermont each year, mosquitoes are mapped out, targeted and trapped. When spotted they are swatted and squished.
The Department of Health in Vermont is interested these mosquitoes is whether or not they are infected with West Nile virus. The west Nile virus is transmitted from infected birds to certain type of mosquitoes that routinely feed on certain birds like robins, jays, crows, ravens and raptors.
Starting June 16, people are encouraged to report all dead by calling 1-800-913-1139.
From these reports the State will be able to monitor and understand more the spread of the West Nile Virus. Information received from West Nile calls and other virus surveillance activities, now in its ninth year, will inform state officials about the level of virus activity and the potential threat to human health.
"Only certain species of birds that are the best indicators of the virus will be tested, but it’s important that people report all dead birds to us," said Health Department epidemiologist Patsy Kelso. "We’ve had an excellent response from Vermonters since we started our surveillance efforts, and it’s been highly successful in raising awareness about West Nile virus."
From last years activities, 370 birds were collected. Of that number 55 were tested and 3 were positive for the West Nile Virus. Though the virus can only be caught when bitten by a mosquitoes (or if you received a blood donation from an infected person), it is advisable to wear gloves when handling dead birds.
On a positive note, there have been no human cases of West Nile virus reported by the Vermont Department of Health for the past four years. In even those bitten by an infected mosquito have a low chance of getting sick. Most people who are infected do not have any symptoms. Fewer than 1 percent of people who are infected develop severe illness, like encephalitis or meningitis. Another 20 percent of people who are infected have a milder illness. People over 50 years of age, and those with weakened immune systems, are at greatest risk for severe illness.
The first case of the West Nile virus in Vermont was first documented in October 2000. when the state bird, a hermit thrush, found dead in southern Vermont tested positive for the virus. In 2002, West Nile virus was widespread among birds and mosquitoes in Vermont. In that same year, the firs human case was documented.
In Maricopa County, Arizona, people have found a unique way to prevent mosquito numbers and the chances of getting the West Nile virus from growing.
For the homeowners of Maricopa County, the prevention is better than cure. That is why they are taking steps in stopping "green pools" from becoming breeding grounds of mosquitoes. In Maricopa County, there has only been one human WNV case reported and they do not wish to add to that.
They are happy to share their secret weapon: a fish called S.S. Minnows. These fish are natives of South America. But what is so important about these Minnows? Minnows actually are mosquito-eating fish. They prefer to feed on mosquito larvae and those little squirmy things on top of the water. Maricopa county owners are having these mosquito killers guard their swimming pools and other bodies of water.
John Townsend from the County Vector Control Program says that homeowners not only get these Minnows for their own properties but also for abandoned houses or swimming pools in their neighborhood. Townsend adds that homeowners `want to either have us (people from the County Vector Control Program) come out and put the fish in or they want to swing by and get some and put them in there themselves." In addition these fish are free from vector control.
What is Vector Control: Vector Control staff investigates citizen complaints dealing with mosquitoes, flies and non-native rodents. They also enforce and ensure compliance of the Maricopa County Environmental Health Code.
Vector Control inspectors identify routine breeding sites and apply the appropriate treatments. They also perform surveillance activities in their "districts" to identify new or potential breeding sites. They also work in conjunction with State officials in monitoring and testing of mosquito samples that are collected on a monthly basis and tested for arboviruses.
The Vector Control office also provides mosquito eating fish (Gambusia) free to the public, for use in ponds, stock tanks, or any permanent waters a homeowner may have. We also try to educate individuals and citizen groups on mosquito reducing techniques they can use around their home or property to eliminate mosquito breeding. We do this through the use of pamphlets, neighborhood meetings and presentations.