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Wednesday, August 13, 2014
How chikungunya may impact baseball

By Jon Shepherd

Although now overshadowed by the Ebola virus epidemic in several nations in Africa, the arrival and establishment of the chikungunya virus in the Americas had been the emerging infectious disease story. This may not seem at first like a baseball story, but it certainly does have some potential impact on the game.

Rays relief pitcher Joel Peralta contracted the virus during his stay in the Dominican Republic over the All-Star break and spent two weeks on the disabled list with flu-like symptoms and fatigue. Members of Ervin Santana’s family have contracted it as well, and he has sent out a few tweets to spread awareness.

Chikungunya is a mosquito-transmitted disease whose range was largely limited to parts of Africa and India. The virus lives on by person-to-person infection through the bites of two species of mosquito. Once infected, the person suffers from fever for a few days and then has debilitating joint pain for two or more weeks (in extreme cases, the pain can persist for years). The name is derived from the condition victims are in from the joint pain and means "bent up" in Makonde.

All in all, this rather painful disease is not particularly lethal, with a mortality rate of less than 1 percent and acquired immunity to it once infected. The disease does carry with it an increased risk of developing an arthritic condition, though.

The Americas chikungunya epidemic is continuing to spread, rising from seven cases in St. Martin in November to half a million cases throughout the region with most centered in the Caribbean, a major area for Major League Baseball player development. The Dominican Republic has been hit particularly hard, with an epidemic of over 300,000 cases since it appeared on the island in April. At the moment, one out of every 40 people in the country has been infected, and that number is still growing.

That said, it has been difficult to see how the epidemic has affected baseball in the Dominican Republic or Venezuela, where the disease is beginning to take root. After looking at playing time distribution for several teams in the Dominican Summer League, there appears to be no difference compared to last year. That is good because such an epidemic has the potential to sideline players and derail training. The epidemic could also play some havoc with amateur showcases. I was able to find health alerts being issued in several countries, including Mexico, which will be hosting an under-15 national team tournament. The Dominican women’s volleyball team suffered a loss to Italy with three of its players out with chikungunya. I have asked several major league organizations for comment on the epidemic over the past month without anyone wishing to comment.

Things are not so worrying in the United States, where most people suffering from the disease contracted it while on vacation or on missions. At least four cases of localized infections have occurred in Florida, and mosquitoes have tested positive for the disease in Texas, but it is important to note that the range of the mosquito species that can transmit the disease here is limited. The primary driver, the yellow fever mosquito (Aedes aegypti), almost exclusively feeds on people at dawn and dusk and is found only in the most southern regions of states bordering the Gulf of Mexico. The secondary driver, the invasive tiger mosquito (Aedes albopictus), is found throughout the Southeast, Midwest and up along the Appalachians, dog-legging out to Long Island. This second species is a poor vector for chikungunya, however, even though it feeds throughout the day, because it does not exclusively bite humans.

Further inhibiting the spread in the United States is that diseases that are so reliant on person-to-person infection through mosquitoes tend to do poorly when a society uses air conditioning. A study on a dengue fever outbreak along the Texas-Mexico border showed that the air-conditioned Texas side had an infection rate one-seventh of that seen in Mexico. The researchers concluded the primary difference between the two populations was simply the ability to close off a home from the outside world with air conditioning, preventing mosquitoes from spreading the disease as easily.

It would be interesting to find out whether clubs are using the lessons learned with dengue and applying them to their academies in Latin America to try to combat chikungunya. Often, players at the academies are allowed to go home during the weekends. Much more rarely, some players live at home and commute to the academy. A club could conceivably keep its players healthier if it kept them on site while rigging up the dorms with air conditioning. The cost would be minimal, and the impact could be meaningful by reducing the incidence of a disease that could greatly limit a player early in his career.

For more information on chikungunya, consult the Centers for Disease Control and Prevention website.

Jon Shepherd is a toxicologist who writes for Camden Depot of the SweetSpot Network.