News Scan for Jul 02, 2014

More imported US chikungunya
;
Deer density and Lyme disease
;
Campylobacter in chickens
;
Drug-resistant malaria in Laos
;
Dengue in Malaysia

US imported chikungunya cases climb to 114

The number of chikungunya cases imported into the United States rose by 41 in the past week, to 114, the Centers for Disease Control and Prevention (CDC) said in an update yesterday. The number of states reporting imported cases climbed from 22 to 27, plus the US Virgin Islands.

Florida remains the most-affected state, with 34 cases, but it did not report any new cases in the past week. New York and Tennessee have both confirmed 8 imported cases, while California has logged 7.

In addition, Puerto Rico has identified 14 locally acquired cases, a number that has not changed since the CDC's previous update on Jun 24. The US Virgin Islands reported a new imported case; it had previously confirmed a locally acquired chikungunya infection.

Of the 114 imported cases, 110 originated in the Caribbean, 3 on Pacific islands, and 1 in Asia. The CDC had not previously reported any cases imported from the Pacific. The agency said health officials have identified 5 additional cases in residents of other countries visiting the United States.

The CDC said that, from 2006 to 2013, the country had averaged only 28 imported chikungunya cases a year. This year, however, has seen an outbreak in the Caribbean that has now topped 260,000 cases—the first chikungunya outbreak in the Americas.

The CDC said imported cases will likely increase, which might lead to local spread of the virus.
Jul 1 CDC update
Jun 25 CIDRAP News story "
US chikungunya cases jump to 74 in 23 states"

 

Study: Frequency of Lyme disease correlates with deer density

The incidence of Lyme disease in humans can be reduced by thinning the white-tailed deer population in a given area, according to a 13-year-long study yesterday in the Journal of Medical Entomology.

White-tailed deer are the main host for the adult Ixodes scapularis (blacklegged or deer) tick, the vector for Lyme disease. The authors surveyed 90% to 98% of the permanent residents of one community in Connecticut, the state where Lyme disease was originally discovered, six times from 1995 to 2008. They looked for exposure to tick-related disease and the frequency of deer observations.

A controlled deer-reduction program was undertaken, after which not only the number of deer observations but also the frequency of Lyme disease cases were greatly reduced. Specifically, a reduction in deer density to 5.1 deer per square kilometer brought a 76% reduction in tick abundance, 70% reduction in the entomologic risk index, and an 80% reduction in resident-reported cases of Lyme disease.

"Reducing deer populations to levels that reduce the potential for ticks to successfully breed should be an important component of any long-term strategy seeking to reduce the risk of people contracting Lyme disease," the authors concluded. They added that hunter access to deer habitat as well as management tools such as incentive programs and use of bait are important in effective deer-reduction programs.
Jul 1 J Med Entolomol study abstract
Jul 1 Entomological Society of America press release

 

Study: Campylobacter can cause disease in chickens

Scientists have considered Campylobacter to be relatively harmless to chickens, but that belief has been based on studies of non-commercial breeds. A study yesterday in mBio, published by the American Society for Microbiology (ASM), shows that C jejuni can cause disease in commercial breeds.

In the study, UK researchers experimentally infected broiler chickens of four commercial breeds. They found that, while levels of the bacteria in the intestines did not differ by breed, immune response and inflammation did, to the extent that one breed showed damage to the gut mucosa and developed diarrhea. The breeds used were not specified.

"The main implication is that Campylobacter is not always harmless to chickens. This rather changes our view of the biology of this nasty little bug," said lead author Paul Wigley of the Institute for Infection and Global Health at the University of Liverpool, in an ASM news release.

"Interestingly the breeds did not differ in the levels of bacteria we found in their intestines after infection, even when kept to normal slaughter age," said Wigley. "This suggests that chicken breed has little direct effect on the risk of Campylobacter entering the food chain but has a big effect on the health of the birds."

C jejuni is the most frequent cause of foodborne bacterial diarrheal disease in the world, and the CDC estimates it affects about 1.3 million Americans a year, according to the release. Poultry is the most common source of infection.
Jul 1 mBio study
Jul 1 ASM
news release

 

Laos grapples with artemisinin-resistant malaria threat

Though efforts to battle malaria in Laos have substantially cut disease levels over the past few years, the country's government is ramping up efforts to contain artemisinin-resistant strains, which have been found in two provinces, according to a Jun 30 statement from the World Health Organization (WHO) Western Pacific regional office.

At a technical consultation in May in Hanoi, Bouasy Hongvanthong, MD, director of the Centre for Malaria Parasitology and Entomology in Laos, said artemisinin resistance has now been confirmed in Champasack and Attapeu provinces, according to the WHO statement.

Laos is the fifth country in the greater Mekong subregion to confirm parasite resistance to artemisinin. The others are Cambodia, Myanmar, Thailand, and Vietnam, according to the WHO.  Resistance to the drug is a threat, because it is part of first-line combination therapy for malaria infections.

Hongvanthong said that although malaria infections dropped off again in 2013, outbreaks continue in Saravan and Champasack provinces. He said cases and deaths are linked to migration patterns, especially people entering Laos to work on large infrastructure development projects.

Another health official at the meeting said malaria is difficult to control at the border areas, because they are hard to access and because populations are difficult to track. Hongvangthong said urgent efforts are needed to educate workers about preventing the disease, when to seek treatment, and the importance of taking the full course of therapy.
Jun 30 WHO statement
WHO artemisinin Q and A

 

Dengue fever affects 42,000 in Malaysia, killing 82

Cases of dengue fever in Malaysia this year have topped 42,000 and proved fatal for 82 people, a death toll more than triple the number at this time last year, Agence France-Presse (AFP) reported yesterday.

The outbreak could prove the deadliest yet for the nation. In 2010 the painful mosquito-borne disease killed 134, an all-time high. In all of last year the country had more than 43,000 cases, with 92 deaths. The disease killed 25 in 2012, AFP reported.

The country has set up a task force to combat the threat, Prime Minister Najib Razak said yesterday, and officials are urging people to practice mosquito-control measures such as eliminating standing water. They have also asked those with symptoms such as nausea, headache, and severe muscle and joint pain to seek medical care.
Jul 1 AFP story

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