Chikungunya virus hits the US and Europe
Chikungunya is on the move. Locally acquired cases of the mosquito-borne virus, native to central Africa, have been identified in the US for the first time, and virologists are warning it could spread to Europe. At the same time, the virus is rampaging across the Caribbean, which has seen a 24 per cent increase in cases in the last week alone.
The virus, which causes rash, fever and severe joint pain, has exploded in Central America and the Caribbean since its arrival in the western hemisphere last December. As of 18 July, the number of cases identified across the Caribbean and parts of the surrounding mainland this year is 442,000 – a 24 per cent rise on last week’s figure.
The Dominican Republic is especially hard hit, with more than 250,000 sick. So too are Haiti, Guadeloupe and Martinique, which have each identified between 50,000 and 63,000 cases. The virus is also spreading in El Salvador, Costa Rica, Venezuela, Guyana, French Guiana and Suriname on the mainland. The virus is rarely lethal, but 26 people have died in the epidemic so far. Many survivors have lasting pain.
Viral souvenirs
Visitors to these countries risk spreading the virus to areas where the two species of mosquito that transmit it are found. That includes the US: one of the mosquito species is found in 14 states, while the other is present in 32.
To date, 234 cases of chikungunya are thought to have been “imported” into the US, but that figure might be ten times higher because many cases are missed or misdiagnosed, warned Harold Noel of the French Institute for Public Health Surveillance (INVS) in an editorial published last week.
More worryingly, last week health authorities also confirmed the first two locally acquired cases of chikungunya in Florida, where both species of mosquito live.
When a virus first affects a population, no one will have developed immunity. “We’re seeing an epidemic ripping through a naive population, with a very large number of cases in the Dominican Republic and elsewhere,” says Peter Hotez of Baylor College of Medicine in Houston, Texas. “There is every reason to believe we could see similar epidemics along the US Gulf Coast maybe later this summer or starting next year.”
Set to spread
European countries are also at risk. Health authorities in France have confirmed 475 imported cases of chikungunya so far this year, up from 17 in 2012. Of these, 126 were identified in regions that have the mosquitoes.
Researchers at the INVS have warned that as mosquito populations climb this summer, and travellers return from French Caribbean islands, conditions are ripe for the virus to spread in southern France.
At the same time, Spanish health authorities have diagnosed 10 imported cases of the virus since April. Five of these were in regions known to have mosquitoes that transmit the virus.
No treatment
Currently, there is no specific treatment available for chikunyunga. Drugs and vaccines are in development, but are only in the early stages of testing, write Anthony Fauci and David Morens of the National Institutes for Allergy and Infectious Disease in the US.
“Licensure is not imminent for any vaccine,” the pair warn. Even when vaccines are available, it will be hard to devise a vaccination strategy, since flare-ups of the virus in endemic regions are unpredictable. The best bet for tackling the disease, they say, will be mosquito control. In that case, chikungunya’s advance seems likely to continue in the impoverished mainland of South America and poor districts of the US.
The virus, which causes rash, fever and severe joint pain, has exploded in Central America and the Caribbean since its arrival in the western hemisphere last December. As of 18 July, the number of cases identified across the Caribbean and parts of the surrounding mainland this year is 442,000 – a 24 per cent rise on last week’s figure.
The Dominican Republic is especially hard hit, with more than 250,000 sick. So too are Haiti, Guadeloupe and Martinique, which have each identified between 50,000 and 63,000 cases. The virus is also spreading in El Salvador, Costa Rica, Venezuela, Guyana, French Guiana and Suriname on the mainland. The virus is rarely lethal, but 26 people have died in the epidemic so far. Many survivors have lasting pain.
Viral souvenirs
Visitors to these countries risk spreading the virus to areas where the two species of mosquito that transmit it are found. That includes the US: one of the mosquito species is found in 14 states, while the other is present in 32.
To date, 234 cases of chikungunya are thought to have been “imported” into the US, but that figure might be ten times higher because many cases are missed or misdiagnosed, warned Harold Noel of the French Institute for Public Health Surveillance (INVS) in an editorial published last week.
More worryingly, last week health authorities also confirmed the first two locally acquired cases of chikungunya in Florida, where both species of mosquito live.
When a virus first affects a population, no one will have developed immunity. “We’re seeing an epidemic ripping through a naive population, with a very large number of cases in the Dominican Republic and elsewhere,” says Peter Hotez of Baylor College of Medicine in Houston, Texas. “There is every reason to believe we could see similar epidemics along the US Gulf Coast maybe later this summer or starting next year.”
Set to spread
European countries are also at risk. Health authorities in France have confirmed 475 imported cases of chikungunya so far this year, up from 17 in 2012. Of these, 126 were identified in regions that have the mosquitoes.
Researchers at the INVS have warned that as mosquito populations climb this summer, and travellers return from French Caribbean islands, conditions are ripe for the virus to spread in southern France.
At the same time, Spanish health authorities have diagnosed 10 imported cases of the virus since April. Five of these were in regions known to have mosquitoes that transmit the virus.
No treatment
Currently, there is no specific treatment available for chikunyunga. Drugs and vaccines are in development, but are only in the early stages of testing, write Anthony Fauci and David Morens of the National Institutes for Allergy and Infectious Disease in the US.
“Licensure is not imminent for any vaccine,” the pair warn. Even when vaccines are available, it will be hard to devise a vaccination strategy, since flare-ups of the virus in endemic regions are unpredictable. The best bet for tackling the disease, they say, will be mosquito control. In that case, chikungunya’s advance seems likely to continue in the impoverished mainland of South America and poor districts of the US.
You can return to the main Market News page, or press the Back button on your browser.
