Chikungunya Virus: The Latest Exotic Illness in the U.S.

Another disease previously not documented to have been acquired in the  continental US surfaced this month. A case of Chikungunya virus infection was diagnosed in a man in Florida on about July 15th, and in a Florida woman shortly thereafter.. I have to admit that this caught my eye primarily because of the unusual name of the disease.  I could not remember having learned about Chikungunya in my training, so I looked it up. The Chijungunya virus appears to have cropped up in the Mosquite imageCaribbean Islands in late 2013 and now just months later has surfaced in Florida in persons who have not travelled to areas with prior cases. Previously the areas where Chikungunya virus was endemic were limited to Africa and some parts of Asia. Two species of the Aedes mosquito found in the southern, eastern and mid-west US are the vector that can spread this virus.

Chikungunya virus is one of a family of viruses called “alpha viruses” which are single stranded RNA viruses. Many of these alpha viruses cause mosquito transmitted diseases.  Other examples include a number of exotic sounding illnesses including the Barmah Forest Disease Complex and the Eastern Equine encephalitis complex.  The Dengue Fever virus is another mosquito borne illness clinically similar to Chikungunya viral which is also a single stranded RNA virus, though not in the alpha virus family.  Dengue Fever was rediscovered in Key West, Florida several years ago and population based antibody testing showed that a high percentage of the residents of Key West had exposure to the Dengue Fever virus.  Unlike Dengue Fever, where many who contact the virus have a very mild illness or no illness, most persons who contact the Chikungunya virus have a moderate to severe illness.

The typical illness of Chikungunya Viral illness usually starts 3-7 days after the mosquito bite that transmits the infection and starts abruptly with fever of 102 degrees or higher and severe joint pains.  The joint symptoms are typically noted on both sides of the body in a symmetric pattern, and can be quite severe.  Other typical symptoms include headache, joint swelling, muscle pain, conjunctivitis intestinal symptoms including nausea and vomiting and a raised rash.

Unlike Dengue Fever where fatalities are not rare and where specific supportive care is important to reduce the chances of life-threatening complications, with Chikungunya virus illness life threatening complications are extremely rare.  The illness can be quite prolonged and recovery can be slow and painful though.

According the the CDC web site:

“The differential diagnosis of chikungunya virus infection varies based on place of residence, travel history, and exposures. Dengue and chikungunya viruses are transmitted by the same mosquitoes and have similar clinical features. The two viruses can circulate in the same area and can cause occasional co-infections in the same patient. Chikungunya virus infection is more likely to cause high fever, severe arthralgia, arthritis, rash, and lymphopenia, while dengue virus infection is more likely to cause neutropenia, thrombocytopenia, hemorrhage, shock, and death. It is important to rule out dengue virus infection because proper clinical management of dengue can improve outcome.”

Diagnostic blood testing for the Chikungunya virus is possible by testing either for virus specific proteins or for the IgM antibodies specific to the virus that are the first immune globulin response to infection.  The CDC, some health departments, and one commercial laboratory can do this testing, and each state health department can give guidance as to the best way to do blood testing in each state.

The CDC does not feel that sustained local pockets of infection are likely to become established in the US.

 

 

Another disease previously not documented to have been acquired in the  continental US surfaced this month. A case of Chikungunya virus infection was diagnosed in a man in Florida this week. I have to admit that this caught my eye primarily because of the unusual name of the disease.  I could not remember having learned about Chikungunya in my training, so I looked it up.

Chikungunya virus is one of a family of viruses called “alpha viruses” which are single stranded RNA viruses that tend to be mosquito transmitted diseases.  Other examples include a number of exotic sounding illnesses including the Barmah Forest Disease Complex and the Eastern Equine encephalitis complex.  The Dengue Fever virus is another mosquito borne illness clinically similar to Chikungunya viral which is also a single stranded RNA virus, though not in the alpha virus family.  Dengue Fever was rediscovered in Key West, Florida several years ago and population based antibody testing showed that a high percentage of the residents of Key West had exposure to the Dengue Fever virus.  Unlike Dengue Fever, where many who contact the virus have a very mild illness or no illness, most persons who contact the Chikungunya virus have a moderate to severe illness.

The typical illness of Chikungunya Viral illness usually starts 3-7 days after the mosquito bite that transmits the infection and starts abruptly with fever of 102 degrees or higher and severe joint pains.  The joint symptoms are typically noted on both sides of the body in a symmetric pattern, and can be quite severe.  Other typical symptoms include headache, joint swelling, muscle pain, conjunctivitis intestinal symptoms including nausea and vomiting and a raised rash.

Unlike Dengue Fever where fatalities are not rare and where specific supportive care is important to reduce the chances of life-threatening complications, with Chikungunya virus illness life threatening complications are extremely rare.  The illness can be quite prolonged and recovery can be slow and painful though.

According the the CDC web site:

The differential diagnosis of chikungunya virus infection varies based on place of residence, travel history, and exposures. Dengue and chikungunya viruses are transmitted by the same mosquitoes and have similar clinical features. The two viruses can circulate in the same area and can cause occasional co-infections in the same patient. Chikungunya virus infection is more likely to cause high fever, severe arthralgia, arthritis, rash, and lymphopenia, while dengue virus infection is more likely to cause neutropenia, thrombocytopenia, hemorrhage, shock, and death. It is important to rule out dengue virus infection because proper clinical management of dengue can improve outcome.

Diagnostic blood testing for the Chikungunya virus is possible by testing either for virus specific proteins or for the IgM antibodies specific to the virus that are the first immune globulin response to infection.  The CDC, some health departments, and one commercial laboratory can do this testing, and each state health department can give guidance as to the best way to do blood testing in each state.

The CDC does not feel that sustained local pockets of infection are likely to become established in the US.

 

 

Chikungunya virus is one of a family of viruses called “alpha viruses” which are single stranded RNA viruses that tend to be mosquito transmitted diseases.  Other examples include a number of exotic sounding illnesses including the Barmah Forest Disease Complex and the Eastern Equine encephalitis complex.  The Dengue Fever virus is another mosquito borne illness clinically similar to Chikungunya viral which is also a single stranded RNA virus, though not in the alpha virus family.  Dengue Fever was rediscovered in Key West, Florida several years ago and population based antibody testing showed that a high percentage of the residents of Key West had exposure to the Dengue Fever virus.  Unlike Dengue Fever, where many who contact the virus have a very mild illness or no illness, most persons who contact the Chikungunya virus have a moderate to severe illness.

The typical illness of Chikungunya Viral illness usually starts 3-7 days after the mosquito bite that transmits the infection and starts abruptly with fever of 102 degrees or higher and severe joint pains.  The joint symptoms are typically noted on both sides of the body in a symmetric pattern, and can be quite severe.  Other typical symptoms include headache, joint swelling, muscle pain, conjunctivitis intestinal symptoms including nausea and vomiting and a raised rash.

Unlike Dengue Fever where fatalities are not rare and where specific supportive care is important to reduce the chances of life-threatening complications, with Chikungunya virus illness life threatening complications are extremely rare.  The illness can be quite prolonged and recovery can be slow and painful though.

According the the CDC web site:

The differential diagnosis of chikungunya virus infection varies based on place of residence, travel history, and exposures. Dengue and chikungunya viruses are transmitted by the same mosquitoes and have similar clinical features. The two viruses can circulate in the same area and can cause occasional co-infections in the same patient. Chikungunya virus infection is more likely to cause high fever, severe arthralgia, arthritis, rash, and lymphopenia, while dengue virus infection is more likely to cause neutropenia, thrombocytopenia, hemorrhage, shock, and death. It is important to rule out dengue virus infection because proper clinical management of dengue can improve outcome.

Diagnostic blood testing for the Chikungunya virus is possible by testing either for virus specific proteins or for the IgM antibodies specific to the virus that are the first immune globulin response to infection.  The CDC, some health departments, and one commercial laboratory can do this testing, and each state health department can give guidance as to the best way to do blood testing in each state.

The CDC does not feel that sustained local pockets of infection are likely to become established in the US.

 

 

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