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Vol. V, No. 10~ EINet News Briefs ~ May 31, 2002

****A free service of the APEC Emerging Infections Network*****

The EINet listserv was created to foster discussion, networking, and collaboration in the area of emerging infectious diseases (EID's) among academicians, scientists, and policy makers in the Asia–Pacific region. We strongly encourage you to share their perspectives and experiences, as your participation directly contributes to the richness of the "electronic discussions" that occur. To respond to the listserv, use the reply function.

In this edition:
  1. Infectious disease information
  2. Updates
  3. Notices
  4. Journal Articles
  5. How to join the EINet listserve

Below is a semi–monthly summary of Asia–Pacific emerging infectious diseases.


Brazil (Mato Grosso do Sul) — Leishmaniasis
At least 25 people have been confirmed to be infected with visceral leishmaniasis, also known as kala–azar, in Mato Grosso do Sul, Brazil in 2002. Cases have been confirmed in 12 municipalities, including the capital of the state, Campo Grande. The city most affected, Tres Lagoas, is 340 km from Campo Grande in the bordering area with Sao Paulo, where three people have died of leishmaniasis in 2002. The other deaths occurred in Ribas do Rio Pardo and in Corumba. According to Promed, the Leishmania species in Mato Grosso do Sul is L.chagasi, the vector is Lutzomyia sand flies, and animal reservoirs include dogs, foxes, and opossums. American visceral leishmaniasis has typically been a rural zoonosis, but the sand fly vector now seeks domestic animals and humans due to destruction of natural habitats and the decline in wild hosts. Consequently, infections in the suburbs of towns and cities have increased.

Control measures implemented in 2000 included a serosurvey of dogs, spraying of residual insecticides in houses, and health education campaigns. The Centre for Control of Zoonoses of Campo Grande confirmed leishmaniasis in 16.5 percent of dogs tested in the first three months of 2002 compared to 2.1 percent of dogs tested in the year 2001. In December 2001 diagnostic kits and drugs for treatment were distributed and in January 2002 a course in diagnosis and treatment was held for health workers of the Basic Health Network. On 22 May 2002 the Manager of the Visceral Lieshmaniasis Control Program will visit Tres Lagoas to evaluate the situation. On 7 June 2002 there will be a seminar for health workers in Campo Grande on surveillance, treatment and control.
[Promed 05/20/02; 05/24/02]

Reportedly, approximately 504 people have become ill with shigellosis after eating Greek-style pasta salad thought to be infected with Shigella sonnei, a bacteria that causes diarrheal illness. The salad, made in Toronto, was distributed in grocery stores, hospital cafeterias, delis, and restaurants throughout Canada. Areas in which the salad is known to have been distributed include: Ontario, Quebec, Prince Edward Island, Nova Scotia, New Brunswick, and Newfoundland. The pasta salad was made between 2 and 18 May 2002 and was recalled voluntarily by the company 18 May 2002. Public health officials have been investigating the outbreak and have not yet found the source of contamination. Federal investigators have finished sampling from the company's plant and initial tests of employees at the plant for shigella infection have been negative. A second set of tests are currently under review. [Promed 05/21/02, 05/29/02]

United States — Imported Hantavirus Pulmonary Syndrome
A 29–year–old American man was bitten by a long–tailed mouse on 13 March 2002 in Nahuelbuta Park, Chile, where he was trapping animals and tracking foxes. On 29 March 2002 he had fever and sweats and developed muscle pains, chest tightness, nausea, vomiting, and diarrhea during the next two days. On 1 April 2002 he was admitted to the intensive care unit of a hospital in Temuco, Chile and serology showed IgM but not IgG antibody to hantavirus. His respiratory status quickly improved and he was discharged on 11 Apr 2002, a week after which he returned to the United States. On 29 Apr 2002, he was seen at the Johns Hopkins University Travel Clinic and serum samples yielded both IgM and IgG antibodies to hantavirus. According to a faculty member of the Johns Hopkins Medical Institutions, this is the first case of hantavirus pulmonary syndrome imported into the United States. Earlier in 2002 a traveler to Chile and Argentina was diagnosed with hantavirus pulmonary syndrome after returning to France.
[Promed 05/30/02]


England — Drug–resistant Bacteria
On 17 May 2002 Britain's Public Health Laboratory Service (PHLS) reported the first case of a new type of antibiotic–resistant bacterium to occur in England. The methicillin–resistant Staphylococcus aureus (MRSA) bacterium has also become resistant to vancomycin. According to statements by the PHLS, officials detected a hospital patient who was infected with glycopeptide–intermediate S. aureus (GISA), a strain of the bacterium that has developed low–level resistance to vancomycin, in April 2002. The patient was successfully treated for MRSA through alteration of antibiotics. Since the discovery of MRSA, vancomycin has been the first choice antibiotic used in its treatment. There are other drugs available to treat this new vancomycin–resistant bacterium; however, the new finding emphasizes the importance of careful antibiotic use to minimize the development of resistance. Strains of S. aureus with low–level resistance to vancomycin have been identified before in Japan, the United States and France, as well as in Scotland and Bristol in the United Kingdom. However, this is the first GISA case in England. Investigators have not identified further spread of the new bacterium.
[Reuter Health Online 05/17/02]


Foot and Mouth — South Korea
Four new cases of FMD occurring between 19 May and 20 May 2002 in pigs were confirmed by South Korea, bringing the total number of cases since the outbreak started on 4 May 2002 to 12. The Agriculture Ministry has reported that authorities have gathered, as of 22 May 2002, more than 110,000 animals in their efforts to contain the disease. According to Agriculture Minister Kim Dong–tae, the current FMD situation is under government control and South Korea has only detected cases in a limited area. Of the total positive cases, 10 are located in a 12–mile diameter zone between Yong–In and Ansong cities in Kyonggi province around Seoul. The remaining two cases are outside the town of Chinchon in Chung Chong province. In addition to managing outbreak investigations, South Korea is making efforts to stop the leakage of bloody water from one of the animal burial pits. According to reports, vinyl wrapper in one of the pits was torn when animals were transferred into it. Currently the government is disinfecting the bloody water leaked from the pit and deodorizing the surrounding areas. South Korea plans to kill and bury 16,286 more animals, bringing the total to almost 127,000. According to reports there have been no new reports of suspected FMD.

On 22 May 2002 South Korean police arrested the owner of the first farm infected in the recent foot and mouth disease (FMD) outbreak. According to the Kyonggi provincial police agency, the owner allegedly buried more than 200 dead pigs near his farm between 27 April and 2 May 2002 without notifying officials.
[Reuters 05/19/02; Promed 05/22/02]

Hong Kong — H5N1 Avian Influenza Outbreak
On 24 May 2002 investigators confirmed that the virus in a recent outbreak of avian influenza in Hong Kong differed from the virus in a 1997 outbreak in which six people died. According to a Reuters health report, all the viruses isolated in 2002 were derived originally from the Goose GD㫸 avian influenza virus and none of the recent H5N1 avian influenza virus strains shared the same combination of genes as those found in the 1997 virus. It is thought that the outbreak of disease on local farms was probably caused by a small number of introductions of H5N1 avian influenza virus onto farms, followed by local spread between farms probably due to the movement of people or items associated with the poultry industry. For some farms in very close proximity the virus may have been airborne and spread through contaminated dust.

Hong Kong has been hit by three major outbreaks of avian influenza in the past five years. This year, over 900,000 chickens were killed and in both 1997 and 2001 the entire chicken population of over one million birds was slaughtered. In the 1997 outbreak of avian influenza A (H5N1) infection was confirmed in 18 individuals, six of whom died. In that outbreak humans acquired infection directly from chickens, without an intermediate host. The slaughter of over 1.5 million chickens helped stop the outbreak. Recommendations proposed by the investigation team to decrease the likelihood of an outbreak include the avoidance of contact with markets by farmers, discontinuation of movement of materials between farms, an increased supply of chilled poultry, and introduction of an additional market "rest day" each month for the disinfection of retail markets.
[Reuters 05/24/02]

Brazil (Sao Paulo) — Hantavirus
The Instituto Adolfo Lutz in Sao Paulo, Brazil, has confirmed hantavirus infection in a 29–year–old man from Sao Carlos who died at the beginning of April 2002. According to an official report from the municipal secretary of health of Sao Carlos, the patient developed a high fever and stomach pains a few days after having hiked a rural trail. It is thought that the patient acquired infection from a shelter contaminated with wild rodent excreta. Sao Carlos is close to Araraquara, where the hantavirus Araraquara virus has been isolated in a human. The rodent vector of Ararquara virus has not been identified.
[Promed 05/18/02]


Development of Ebola Vaccine
On 16 May 2002, Crucell NV, a Dutch biotechnology company, announced its collaboration with the US government on the development of a vaccine against Ebola, the filovirus that causes Ebola hemorrhagic fever. The vaccine research center of the National Institutes of Health (NIH), the United States government's major medical research body, has developed Ebola genes that will be used for the vaccine. An experimental vaccine made by the research center succeeded in preventing Ebola in monkeys and the vaccine development will likely be ready for the next stage of development. According to the chief scientific officer at Crucell, the vaccine could be tested in humans within two years and may be available within approximately five or six years. According to Crucell, under the partnership's terms the company will have the option of acquiring exclusive rights to sell the vaccine once it is produced. Under current plans the vaccine will target travelers, government officials, military personnel and people living in Ebola endemic areas.
[Reuters Health Online 05/16/02]

New DTP Vaccine
Aventis Pasteur, the US subsidiary of Aventis SA in France, has been given a license by the US Food and Drug Administration (FDA) to market a new vaccine for diphtheria, tetanus and pertussis (DtaP). The vaccine, named Daptacel, was designed as a multi–dose package excluding the mercury–based preservative thimerosal and will be produced in Canada. In addition, Aventis Pastuer will continue production of its current vaccine, Tripedia, in order to manage the current shortage of DTaP vaccines in the United States. Under current FDA regulations vaccines must be re–formulated to remove thimerosal. Shortages of the vaccine in the United States have occurred due to this change in regulation as well as the termination of vaccine production by US drug maker Wyeth.

The FDA has approved Daptacel for the first four consecutive doses of the childhood immunization series, but the fifth dose remains to be licensed by the FDA. The results of a recent randomized trial published in the New England Journal of Medicine (N Engl J Med 334:349𤭓) suggest that the vaccine has a high level of protection against pertussis. The trial, sponsored by the National Institute of Health, was double–blinded and placebo controlled. According to a company statement, supplies are expected to be available by mid–June. Daptacel is also licensed for use in Canada.
[Reuters Health Online 05/16/02; Gustafsson L, Hallander HO, Olin P, et al. A controlled trial of a two–component acellular, a five–component acellular, and a whole–cell pertussis vaccine. N Engl J Med 1996;334:349𤭓]


Genetically Engineered Malaria–resistant Mosquito
Researchers at Case Western Reserve University in Ohio, United States, and the Universitat Bayreuth in Bayreuth, Germany have taken a transgenic approach to preventing transmission of the malaria parasite Plasmoidium. It is estimated that malaria causes 0.7 to 2.7 million deaths a year; however, this number is thought to be underestimated due to under–reporting and difficulties of diagnosis. Control of the disease has been difficult due to drug resistance in the parasites, insecticide resistance in the mosquitoes, and lack of an effective vaccine. The scientists introduced a synthetic gene in to the germline of culicine and anopheline mosquitoes in order to express antiparasitic peptides in the midgut of mosquitoes. Once inside a mosquito, the malaria parasite needs to cross gut epithelium and into the blood in order to fully develop. Jacobs–Lorena and colleagues identified a peptides called SM1 that attaches itself to the gut wall of the mosquito and essentially acts by blocking the parasite. They then constructed a synthetic gene that produces SM1 when the mosquito feeds on contaminated blood.

Through their research, which has been published in the May 23rd issue of Nature (Nature 417:387פ), the scientists found that expression of the SM1 peptide in the mosquito midgut inhibited Plasmodium development. The genetically modified mosquitoes were less susceptible to infection after feeding on a malaria–infected mouse and were far less able to transmit the malaria parasite to mice than normal mosquitoes. Both groups of mosquitoes studied were unable to transmit the parasite and one group had a 50 percent reduction in transmission. The study investigated transmission in mice so it is not yet known if SM1 will block transmission of human malaria parasites. Another major obstacle in the use of these genetically modified mosquitoes is that it is not clear if there is a safe and effective way to spread foreign genes across mosquito populations. What's more, because the technique was not fully effective at blocking transmission, resistant variants may be selected and little is known about how genetically engineered mosquitoes may affect the genes of mosquitoes in the wild.
[Nature 2002;417:387פ, 452ס]

Timing and Effectiveness of Measles Vaccination
A recent study published in the Mayo Clinic Proceedings examined the relationship between antibody levels and measles immunizations in US children at 15 months of age compared to Canadian children at 12 months of age. Measles, which can lead to serious complications, is a highly contagious viral infection that causes a rash, high fever, coughing and other symptoms. In the United States, children receive two doses of the measles–mumps–rubella (MMR) vaccine, one dose at 12 to 15 months of age and the second around 4 to 6 years of age.

Results of the study by Dr. Gregory A. Poland of the Mayo Clinic in the United States and colleagues suggest that children who are vaccinated closer to 15 months of age may gain better protection against measles compared with those who are immunized around 12 months of age. Investigators evaluated 333 children who were immunized against measles at 12 months and 719 children immunized closer to 15 months. All of the children were between the ages of 6 and 11 years and had only one dose of measles vaccine, as had been recommendations at that time. Overall, 87 percent of the US children and 76 percent of the Canadian children had measles–fighting antibodies in their blood (P< 0.001). After adjusting for time from immunization and age of immunization, differences in seropositive rates were no longer significant (OR = 1.53, 95%CI = 0.87מ.69). However, the researchers observed a significant dose–response relationship between the age at immunization and the likelihood of being seropositive after immunization. The authors concluded that the current US policy of immunizing with a first dose at 12 months of age may be less effective than immunizing at 12 to 15 months of age.
[Mayo Clinic Proceedings 2002;77:446𤮴 Reuters Health Online 05/16/02]

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