Minnesota Department of Health (MDH) Bug Bytes
March 14, 2001
Vol. 2: No. 6
Three cases of invasive meningococcal disease have been reported in the last 2 weeks. The first, a 4-year old male, was initially reported as a suspect case when he was admitted to the hospital with purpura fulminans. His blood culture grew out Neisseria meningitidis later, but prompt notification made it possible to quickly determine which contacts should be treated with prophylactic antibiotics. In addition to his immediate family and other close contacts a local health department and we determined that approximately 40 preschool classroom and church school classroom contacts should be given prophylaxis. The second case was a 49-year-old male with abrupt onset of illness. He became hypotensive, developed a petechial rash, had multisystem organ failure, and died within 24 hours of his initial symptoms. The family was started on antibiotics at the time of admission as a precautionary measure. The physician promptly notified us when gram negative diplococci were identified in the blood culture. A family member was interviewed about other possible contacts who might need prophylaxis. Neisseria meningitidis was subsequently isolated from blood culture. The third case was a 20-year-old female admitted to a hospital with meningococcemia. Prophylaxis was recommended to approximately 20 attendees of a party, attended by the case-patient, who may have shared oral secretions with her. Neisseria meningitidis was subsequently isolated from blood culture. Isolates from all cases were sent to us for serogrouping; the first two were serogroup Y and the third is pending. There is no known connection between the first two cases and the isolates have different pulsed-field gel electrophoresis patterns. Approximately 40 sporadic cases of invasive meningococcal disease are reported in Minnesota annually. In 1999, 56 cases were reported, followed by 22 cases in 2000, and only 4 cases (including the 3 described here) have been reported so far in 2001. It is unknown why there has been a drop in cases. It is important that MDH be notified promptly of suspect cases of meningococcal disease. In some instances it may not be possible to have culture confirmation but chemoprophylaxis of contacts may be recommended based on the case's clinical picture and related circumstances. The American Academy of Pediatrics Red Book recommends that high risk contacts begin chemoprophylaxis within 24 hours of diagnosis of the primary case.
2. Second Measles Case Seen In the last issue of Bug Bytes we discussed an imported case of measles in an infant adopted from China. We now have another measles case with no association to the first case. On February 28, a clinic reported a suspect measles case in a 31-year old Hennepin County resident. He had symptoms of cough, coryza, and conjunctivitis beginning on February 25, and rash on February 26. Blood drawn on February 28 and was negative for IgG and IgM measles antibody (indicating his susceptibility to measles and an insufficient time for IgM antibody to develop). Although CDC recommends obtaining serology on the first day of rash, our experience indicates that waiting until day 3 (72 hours) is optimal to avoid false negative results. A second blood was drawn on March 5 and was positive IgM antibody. The patient traveled extensively for business to California and Texas, but we are unable to determine a specific exposure for him. Measles cases have been seen in 11 states in the last month. He believes he had received one dose of vaccine as a child. On a related note, we have seen no secondary spread from the first infant case, but cases are still possible at this point in time.
3. Chronic Wasting Disease of Deer and Elk
A common telephone call received lately involves whether or not venison or elk is safe to eat, the caller having heard about "mad cow disease in deer." In a previous (Dec. 1, 2000) Bug Bytes we discussed mad cow disease and Creutzfeldt-Jakob disease. Chronic wasting disease (CWD) is another type of transmissible spongiform encephalopathy (TSE) of deer and elk. First seen in 1967, among free ranging wildlife, it is confined to mule deer, white-tailed deer, and Rocky Mountain elk in northeastern Colorado, southeastern Wyoming, and very recently in Nebraska. It has also been seen sporadically in farmed elk herds in South Dakota, Nebraska, and Oklahoma. Fewer than 200 animals have been diagnosed with CWD with an estimated prevalence of <5% in wild deer and <1% in wild elk in the affected area. It has never been found in Minnesota. Like other TSEs it is a progressive fatal neurodegenerative disease. Its origin and mode of transmission is unknown. CWD is not known to cross over to other species and humans are not thought to be at risk. As a precautionary measure, Colorado health officials advise hunters to not eat obviously ill animals; wear gloves when gutting a carcass; and to not eat brain, spinal cord, eye, or lymph nodes where the transmissible agent is thought to be present.
4. Foot and Mouth Disease
Another common telephone call received lately is about the foot and mouth disease (FMD) epidemic being seen in the U.K. and several European countries. FMD is a highly infectious viral disease of cloven-hooved animals, especially cattle, pigs, sheep, and goats. The disease causes fever and blisters in the mouth and on the feet of animals. It may lead to lameness, drop in milk production, and weight loss in infected animals, with severe economic consequences for the farmer. Very few human FMD infections have ever been documented despite regular exposure throughout the world. It has been found in those with direct contact to infected animals. Those few have had a self-limiting mild influenza-like illness (headache, malaise, fever). They also may exhibit symptoms similar to animals with vesicles appearing on the fingers and hands, feet, and in the mouth, especially the tongue and palate. It is not transmitted person-to-person or through food to humans. It should not be confused with hand, foot, and mouth disease in humans (a mild viral illness caused by a different enterovirus). With this information in mind, we've been advising people not to cancel their travel plans to Europe, but to use caution so as not to bring the virus back to Minnesota farms. The Board of Animal Health recommends avoiding visiting farms and zoos in Europe, and to wash clothes and shoes, and to not visit farms for 7 days after returning to Minnesota. Information about the foot and mouth outbreak is at http://www.maff.gov.uk/animalh/
diseases/fmd/default.htm Attention: Non-MDH link
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