Evolution of chik-V
THE EDITOR, Sir: So much has been written and said about chikungunya that most Jamaicans are either experts or pseudo-experts on this disease. This brief article is intended to add a few facts about the disease that readers may find interesting.
The word chikungunya means "that which bends up". The first recorded outbreak was in 1779 but molecular genetic evidence suggests that it evolved around 1700. The most recent outbreak of this disease occurred in 1952 in the area where Tanzania borders Mozambique. The first recorded case in the Caribbean was in St Maarten. Despite the wide dispersion there are some Caribbean islands where there are no recorded cases to date.
Monkeys, apes and rodents act as reservoirs of the disease. We may not have many monkeys in Jamaica but we certainly have lots of rodents. The call for improved garbage collection and the cessation of illegal dumping of domestic refuse is not without merit.
There are two diagnostic tests for chikungunya. They are RT-PCR and IgM/IgG antibody tests. The chikungunya is a RNA virus. The RT-PCR (Reverse Transcription- Polymerase Chain Reaction) test will detect the RNA soon after the onset of symptoms.
This is an obvious advantage for rapid confirmation of diagnosis. However, the test can become negative in the later stages of the disease. On the other hand the IgM/IgG antibody tests will be negative in the early stages but will become positive in the later stages. This latter test has the advantage of confirming that a patient had the disease and will be very important in vector control and regional epidemiology.
The symptoms of chikungunya are well known. It is also well known that dengue and other viral infections may mimic chikungunya. Accurate diagnosis is important especially in certain clinical groups. Expectant mothers who contract the virus one week before delivery can pass a very severe form of the disease to the newborn. The joint pains associated with the extreme forms of the disease can persist for years.
Chik-V is the common abbreviation for the name of the virus. It has certainly made it easier for persons who cannot pronounce the multi-syllable, tongue-twisting chikungunya.
TREVOR A. CAMPBELL