Update

Trypanosoma cruzi in Tennessee

Source: Herwaldt BL, et al. J Infect Dis 2000;181:395-399.

In july 1998, in rural rutherford, Tenn., a mother found an unusual bug in the crib of her 18-month-old son, as well as black spots on the sheets (which had not been changed in 3 weeks). She had never seen this bug before, although she recalled something similar on a recent television program about insects that feed on mammals. Concerned, she took the bug to a local university, where much to everyone’s surprise, it was identified as an adult female Triatoma sanguisa. The bug was engorged with blood, and its’ intestines were stuffed with motile trypomastigotes of Trypanosoma cruzi (remember that large black posterior kinetoplast?). Within weeks, the boy developed intermittent fever. Although multiple blood tests for T. cruzi antibody and buffy coats were negative (and remained negative for the next 10 months), three separate blood specimens obtained over a three-week period were positive by PCR and DNA hybridization, suggesting that he had persistent low-level parasitemia. He was, therefore, treated with benznidazole for eight weeks with no recurrence of his symptoms and no further evidence of infection.

Investigators exploring the area around the house, which was clean and well built, turned up only one T. sanguisuga nymph in a wood pile on a nearby farm. In addition, two dogs on the farm, as well as eight rodents and nine other feral mammals in the area, were tested. Two of the raccoons were actively infected, and one dog had high antibody titers to T. cruzi. Two additional adult female bugs were found in the basement and on the front porch the following spring.

At least a dozen species of reduviid bugs—including this triatome—serve as the primary vector for T. cruzi. In addition, T. cruzi has been reported in 18 different species of mammals in the United States, including Maryland, Georgia, Florida, Arizona, Texas, Utah, and California. Although serological evidence of human infection has been reported in California and Georgia, this is only the fifth reported case of autochthonous human infection in the United States. Remarkably, this case would not have been recognized without the intervention of a very perceptive mom as well as newer molecular diagnostic techniques.

The adult female Triatoma sanguisa found in the baby crib of an 18-month-old in rural Tennessee was carrying Trypanosoma cruzi.

a. True

b. False


British Dog Makes History!

Source: ProMED mail posting. www.promedmail.org, Feb 11, 2000.

The british minister of agricul- ture and the Royal Marine Bugle Corps welcomed home Adan, a seeing-eye dog, and his owner on Feb. 8, 2000, after a historic five-day trip to France. Adan is the first dog to legally exit and reenter Great Britain without the requisite six-month quarantine. His owner is a 78-year-old former Royal Marine Commando who was injured in the Normandy Campaign, who requested the assistance of his seeing-eye dog in order to visit battlesites and the graves of former Commandos.

Adan’s owner was granted a special dispensation three weeks in advance of implementation of Britain’s new pilot Pet Travel Scheme. This new policy, which is being tested for one year, allows only cats and dogs who visit certain western countries permission to exit and reenter the country. Owners must still meet fairly rigid requirements, including having all animals registered through microchip technology, certain blood tests and immunizations must be current, and all animals must be cleared by a veterinarian before departure, again in the country they visit, and within 24-48 hours of reentering British soil.

While pet owners welcomed this news, one expert notes that the greatest benefit will be to service and work dogs, such as seeing-eye dogs and the dogs deployed to assist in the aftermath of the recent earthquakes in Turkey. Lengthy quarantines are detrimental to these animals, who require ongoing training to maintain their strength and skills.


Is Malaria in Cancun a Problem?

Source: ISTM Travel Medicine list; TRAVELMED@YORKU.CA; Jan. 31-Feb. 1, 2000.

Following a two-week christmas vacation to Cancun, Mexico, two Canadians have been diagnosed with Plasmodium vivax malaria. Both travelers had limited their activities to Cancun and the adjoining beaches and had not ventured beyond the city limits. This report is being reviewed by Canadian health authorities, who have the authority to alter recommendations for travel. Because acquisition of P. vivax in the major Central American resort areas along the Pacific and Gulf Coasts is uncommon, malaria prophylaxis is generally not recommended (www.cdc.gov/travel/camerica/htm). However, malaria is present throughout the year in rural areas. Malaria prophylaxis is, therefore, recommended for the more rural areas of places like Belize and Costa Rica, although it has been my experience that few American travelers are appraised of this by their travel agents or primary care providers.

This case reminds me of when I took care of a local housewife who spent one week each year with six of her friends relaxing on the island beaches off of Honduras. After her last trip, she required hospitalization for vivax malaria. She reluctantly explained to me that, although they had routinely taken malaria prophylaxis for each of the previous six years, she elected to forego it for this trip because none of them had gotten malaria before!

Two Canadians contracted malaria after vacationing in:

a. Costa Rica.

b. Honduras.

c. Mexico.

d. Belize.

e. Great Britain.