Mosquitoes carry painful Chikungunya virus to other countries

The patient showed up at a hospital feverish and hobbled by joint pain, a rash spreading across her face, and was presumed to be suffering from lupus or severe rheumatoid arthritis.

But in talking to the middle-aged woman recently, doctors realised that her symptoms and recent history of travel to the Dominican Republic added up to a different diagnosis: chikungunya, an infectious disease carried by the same mosquitoes that spread dengue fever.

Chikungunya has plagued other parts of the world — particularly Asia and Africa — for decades, becoming more prevalent in recent years.

But it arrived in the Caribbean only in December and has already infected as many as 250 000 people there.

According to a health report produced on Tuesday, Zimbabwe is among countries that reported chikungunya virus transmission.

The virus is generally not lethal and can’t pass from person to person.

But the pain it brings can be horrible — some who have weathered its wrath have said they wished the virus had killed them.

In rare cases, the agony can last for months or even years.

Public health officials in the Caribbean are reportedly struggling to contain the outbreak, in part because of the difficulty of limiting mosquito breeding grounds and because the disease is so new to the area.

Paola Lichtenberger, director of the Tropical Medicine Programme at the University of Miami, says she is sure the epidemic is more widespread than official numbers suggest simply because making the diagnosis is so difficult.

Public health officials in the US and around the world, meanwhile, are tracking cases carefully and encouraging people in affected areas to take precautions to avoid infections and to clean up areas of stagnant water.

Airports in 10 major American East Coast cities with Caribbean-bound flights have posted warnings to passengers about chikungunya.

Where has chikungunya virus been found?

Chikungunya occurs in Africa (more specifically West Africa from Senegal to Cameroon, Central and East Africa including Central African Republic, Angola, the Democratic Republic of Congo, Zambia, Zimbabwe, Tanzania, Malawi, Mozambique, eastern Botswana, and north eastern parts of South Africa; there is also evidence of viral presence in parts of Ethiopia and Sudan), and Asia (India, Sri Lanka, Thailand, Myanmar, Malaysia, Indonesia, Philippines and Cambodia).

Outbreaks have also been reported in Saudi Arabia, Papua New Guinea, on islands in the Indian Ocean, including Réunion, Mayotte, Mauritius, and the Seychelles.

In late 2013, the first local transmission of chikungunya virus in the Americas was identified in Caribbean countries and territories.

Local transmission means that mosquitoes in the area have been infected with the virus and are spreading it to people.

Protect yourself from mosquito bites

Use air conditioning or window/door screens to keep mosquitoes outside. If you are not able to protect yourself from mosquitoes inside your home or hotel, sleep under a mosquito bed net.

Help reduce the number of mosquitoes outside your home or hotel room by emptying standing water from containers such as flowerpots or buckets.

When weather permits, wear long-sleeved shirts and long pants.

Use insect repellents

Repellents containing DEET, picaridin, IR3535, and oil of lemon eucalyptus and para-menthane-diol products provide long lasting protection.

If you use both sunscreen and insect repellent, apply the sunscreen first and then the repellent.

Do not spray repellent on the skin under your clothing.

Treat clothing with permethrin or purchase permethrin-treated clothing.

Always follow the label instructions when using insect repellent or sunscreen.

If you have chikungunya , follow these instructions:

During the first week of infection, chikungunya virus can be found in the blood and passed from an infected person to another mosquito through mosquito bites. An infected mosquito can then transmit the virus to other people.

To prevent further spread of the virus, it is important for people to avoid mosquito bites during the first week of illness.
But it’s only a matter of time before that happens, according to Lichtenberger, who has helped treat three chikungunya patients since the outbreak began.

“I’m pretty sure we’re going to have cases here, if we already haven’t had them,” she says.

Symptoms, diagnosis, & treatment

Symptoms
Most people infected with chikungunya virus will develop some symptoms.

Symptoms usually begin 3–7 days after being bitten by an infected mosquito.

The most common symptoms are fever and joint pain.

Other symptoms may include headache, muscle pain, joint swelling, or rash.

Chikungunya disease does not often result in death, but the symptoms can be severe and disabling.

Most patients feel better within a week. In some people, the joint pain may persist for months.

People at risk for more severe disease include newborns infected around the time of birth, older adults (≥65 years), and people with medical conditions such as high blood pressure, diabetes, or heart disease.

Once a person has been infected, he or she is likely to be protected from future infections.

Diagnosis

The symptoms of chikungunya are similar to those of dengue, another disease spread by mosquitoes.

See your doctor if you develop the symptoms described above.
If you have recently traveled, tell your doctor.
Your doctor may order blood tests to look for chikungunya or other similar diseases.

Treatment
There is no medicine to treat chikungunya
virus infection or disease.

Decrease the symptoms:
• Get plenty of rest
• Drink fluids to prevent dehydration
• Take medicines, such as ibuprofen, naproxen, acetaminophen, or paracetamol, to relieve fever and pain

Transmission 
Through mosquito bites
Chikungunya virus is transmitted to people through mosquito bites. Mosquitoes become infected when they feed on a person already infected with the virus.

Infected mosquitoes can then spread the virus to other people through bites.

Chikungunya virus is most often spread to people by Aedes aegypti and Aedes albopictus mosquitoes.

These are the same mosquitoes that transmit dengue virus. They bite mostly during the daytime.

Aedes mosquitoes transmit chikungunya virus to people. These types of mosquitoes are found throughout much of the world.

Rarely, from mother to child
Chikungunya virus is transmitted rarely from mother to newborn around the time of birth.

Rarely, through infected blood
In theory, the virus could be spread through a blood transfusion. To date, there are no known reports of this happening.

Prevention
No vaccine exists to prevent chikungunya virus infection or disease.

Prevent chikungunya virus infection by avoiding mosquito bites.

The mosquitoes that spread the chikungunya virus bite mostly during the daytime.

When travelling abroad

So far, the Dominican Republic has been hardest hit, with 135 000 suspected cases; Guadeloupe comes next with 40 000, followed by Haiti with 39 000 and Martinique with 35 000.

“The whole Caribbean is just full of it,” Lichtenberger says.

Doctors who had never seen the disease until six months ago struggle with proper diagnosis, she says, especially because chikungunya can look a lot like influenza or dengue — and can even occur together with dengue.

Lichtenberger expects more cases in the continental United States soon.

Someone from the Caribbean who has long planned a vacation or family visit to the US isn’t going to cancel just because mom, dad, or junior feels lousy, Lichtenberger says. If the sick person gets bitten by a mosquito in the US, the virus can easily get transmitted.

That’s why it’s important for sick people to take precautions to protect themselves from further mosquito bites, she says: not for their sake, but for others’.

But Mark Heise, who studies the genetics of disease susceptibility at the University of North Carolina in Chapel Hill, says chikungunya probably won’t spread too far in the United States.

“It’s something we should be concerned about, but I don’t think people need to panic about it either,” he says.

Heise looks at the transmission of dengue as an indicator for how chikungunya is likely to spread. Dengue fever is a major problem in the Caribbean and South and Central America, and there are sporadic cases on US soil, “but it isn’t a major public health threat.”

The type of mosquito that has most often spread chikungunya, Aedes aegypti, does not live in the United States, says Stephen Morse, a virologist and professor of epidemiology at the Mailman School of Public Health at Columbia University in New York.
But its cousin Aedes albopictus, also known as the Asian tiger mosquito, lives as far north as Chicago and is also believed to be able to transmit chikungunya.

The virus tends to burn itself out in a particular community because it strikes so many people so quickly, Morse says. It leaves them with immunity that can last years or even a lifetime.

US disease centres track transmission areas

The United States Centers for Disease Control (CDC) maintains a map with reported current or previous local transmission of chikungunya virus.

Endemic areas — Chikungunyavirus is endemic in parts of west Africa where it appears to be maintained in a cycle involving humans, Aedes mosquitoes, primates, and perhaps other animals. Serosurveys of humans in parts of West Africa have identified antibodies to chikungunya virus in 35 to 50% of the population in the absence of recognised outbreaks.

Spread and resurgence — Chikungunya virus spreads by means of travel of infected individuals between regions where competent mosquitoes exist for perpetuation of local transmission.

Imported cases have been described in many Asian and European countries as well as in the Americas and Australia.

Rapid spread in the last few years may also be related to a viral mutation that enhances replication efficiency in the Aedes albopictus mosquito.

No vaccine, no meds

Chikungunya got its name from the phrase “which bends up” in the local dialect in Tanzania where it was first identified in the early 1950s. The term described the posture of someone with the disease, bent over with pain.

Most victims suffer extreme joint pain for 5-12 days, making it hard for them to grasp things with their hands or put weight on their legs.

The pain usually subsides by the two-week mark, but a small number of patients “continue to have sporadic bouts of joint pain, and we really don’t understand why that is,” Heise says.

People middle-aged and older and those with pre-existing medical conditions tend to suffer more than children and young adults, says Heise, whose research focuses on why the virus replicates in joints and why it causes an overreaction of the immune system.

There is no vaccine or medication that can change the course of the disease, though patients are given painkillers and told to drink a lot of fluids, Morse says.

To avoid getting chikungunya while staying in affected areas, take the usual precautions against mosquitoes: Wear long sleeves, use repellents, and keep outside areas free of stagnant water where mosquitoes can breed.

“Take it very, very seriously,” Lichtenberger says. “Especially where you see a lot of people with the disease and lots of mosquitoes.”

Chikungunya is an arthropod-borne virus (arbovirus) endemic to West Africa that causes acute febrile polyarthralgia and arthritis.

The name chikungunya is derived from a local language of Tanzania meaning “that which bends up” or “stooped walk” because of the incapacitating arthralgia caused by the disease.

Multiple outbreaks beyond West Africa have been described. Since 2004, chikungunya has spread broadly, causing massive outbreaks with explosive onset in the Indian Ocean region, India, and other parts of Asia.

Chikungunya had traditionally been perceived as a tropical disease until an outbreak in Italy in 2007.

In addition, thousands of cases have been identified in travelers returning from outbreak areas.

The distribution of mosquito vectors capable of transmitting chikungunya virus is wide; in the future, transmission could occur in regions with no prior case reports.