By: Stavana Strutz, PhD Candidate, Parmesan Lab, University of Texas at Austin
So back in February I wrote a Parasaturdays post about dengue in the United States. You should have a gander at that page if you're totally unfamiliar with the pathogen. The most recent news besides the new FDA approved test, is evidence of dengue in Houston during the last decade.
So back in February I wrote a Parasaturdays post about dengue in the United States. You should have a gander at that page if you're totally unfamiliar with the pathogen. The most recent news besides the new FDA approved test, is evidence of dengue in Houston during the last decade.
Image via WHO, Engorged Aedes aegypti
Why would anyone even think to test for dengue in Houston when the nearest other United States dengue occurrence is more than 400km away along the Texas/Mexico border? At a recent Diseases in Nature conference in San Antonio and Neglected Tropical Diseases conference in Houston I heard Dr. Kristy Murray from the Baylor College of Medicine speak about how the perfect ecological scenario is brewing in Houston for dengue transmission. Houston has mild winters contributing to the year-round survival of dengue vector mosquito species such as Aedes aegypti and A. albopictus. Additionally, many of Houston's residents travel to dengue endemic areas.
If a handful of those individuals came back with dengue virus in their blood, they could pass it on to the mosquitoes in Houston. Most dengue infected individuals will never even experience symptoms while an unlucky 5% of the infected will experience a severe manifestation that can lead to death. The gross symptoms of dengue are high fever, muscle and joint pain, measles-like rash, mucous membrane bleeding, fatigue and sometimes shock or internal hemorrhaging. This is why I always say if you have flu-like symptoms, a rash, and a recent arthropod bite, you should head to your doctor ASAP.
So back to the point: Murray conducted a retrospective serology study of Houston patients between 2003-05 who had symptoms consistent with arboviral disease. Out of 3768 CSF and serum specimens, 47 had anti-DENV IgM antibody! Eighteen of those patients met the case definition for dengue fever. The other interesting but also sad piece of information from her talk was that two of the positive individuals died. One was a 92 year old woman who had been bedridden for 2 years with no recent travel outside of Houston who I think if I remember correctly did not have air conditioning and would leave her windows open. The other woman, 49 years old, had traveled to Mexico somewhat recently. 84% of the cases who had tested positive via Ab or direct RT-PCR had no travel history to dengue endemic areas!
Basically, Murray and her team found autochthonous transmission to occur in Houston [at least a lot of evidence for it]! Physicians in the Houston area should at least be aware that this is a possibility in the area. It seems as though there has been more education about other tropical/novel pathogens in the United States like Chagas disease and West Nile virus. Here is yet another one to add to the list.
If a handful of those individuals came back with dengue virus in their blood, they could pass it on to the mosquitoes in Houston. Most dengue infected individuals will never even experience symptoms while an unlucky 5% of the infected will experience a severe manifestation that can lead to death. The gross symptoms of dengue are high fever, muscle and joint pain, measles-like rash, mucous membrane bleeding, fatigue and sometimes shock or internal hemorrhaging. This is why I always say if you have flu-like symptoms, a rash, and a recent arthropod bite, you should head to your doctor ASAP.
So back to the point: Murray conducted a retrospective serology study of Houston patients between 2003-05 who had symptoms consistent with arboviral disease. Out of 3768 CSF and serum specimens, 47 had anti-DENV IgM antibody! Eighteen of those patients met the case definition for dengue fever. The other interesting but also sad piece of information from her talk was that two of the positive individuals died. One was a 92 year old woman who had been bedridden for 2 years with no recent travel outside of Houston who I think if I remember correctly did not have air conditioning and would leave her windows open. The other woman, 49 years old, had traveled to Mexico somewhat recently. 84% of the cases who had tested positive via Ab or direct RT-PCR had no travel history to dengue endemic areas!
Basically, Murray and her team found autochthonous transmission to occur in Houston [at least a lot of evidence for it]! Physicians in the Houston area should at least be aware that this is a possibility in the area. It seems as though there has been more education about other tropical/novel pathogens in the United States like Chagas disease and West Nile virus. Here is yet another one to add to the list.
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