News Scan for Dec 20, 2016

WHO H7N9 details
;
MDR-TB in migrants
;
Azithromycin for Lyme

WHO offers more details on H7N9 infections in China, Macau

The World Health Organization (WHO) released two reports today detailing the six human cases of H7N9 in mainland China and one in Macau that were previously confirmed by local officials. All but one patient had direct exposure to live poultry.

From Nov 6 to Nov 20, six men in China from 32 to 80 years old began having flulike symptoms and were later diagnosed as having H7N9. All were hospitalized in severe condition. Five had live-poultry exposure. One patient had no known exposure to poultry or poultry markets. No cluster of cases was reported, and the patients came from three provinces: Jiangsu (4), Fujian (1) and Guangdong (1).

Macao's recent H7N9 case was reported on Dec 14. The man, a poultry vendor, was and remains asymptomatic, and his infection was found in connection with an investigation into live chickens imported from mainland China and sold at a wholesale market. He remains hospitalized and is being treated with antivirals. His wife, who also works at the market, tested negative for the virus and will be monitored for 10 days.

According to the WHO, there have been a total of 807 laboratory-confirmed human infections with avian influenza A (H7N9) virus since early 2013. Officials advise that travelers to areas affected by avian flu should avoid poultry farms, contact with animals in live-bird markets, poultry-slaughtering areas, and contact with surfaces that appear to be contaminated with bird or other animal feces.
Dec 20 WHO China
statement
Dec 20 WHO Macao
statement

 

ECDC investigating small cluster of multidrug-resistant tuberculosis cases

European health officials yesterday reported a 16-case cluster of multidrug-resistant tuberculosis (MDR-TB) involving asylum seekers from the Horn of Africa.

According to a Rapid Risk Assessment from the European Centre for Disease Prevention and Control (ECDC), the first 7 cases were identified in Switzerland between February and August 2016. Somalia is the country of origin for 5 of those patients, with 1 person coming from Ethiopia and 1 from Eritrea. All patients were males aged 15 to 19 years.

Based on the results of whole-genome sequencing (WGS), the strains are highly genetically similar and likely belong to a single molecular cluster. WGS showed no difference among isolates in four cases and differences of one allele in three others. Investigators say the strain of MDR-TB is resistant to rifampicin, isoniazid, ethambutol, pyrazinamide, and capreomycin but is fully sensitive to amikacin and fluoroquinolones.

Since the initial 7 cases were identified, 9 additional cases have been identified among Somali asylum seekers in Germany (6), Austria (2), and Sweden (1). All of these cases involve the same WGS profile, and several have similar drug susceptibility patterns.

Migrants seeking refuge from conflict or economic deprivation are considered at increased risk for TB or MDR-TB because of poor health services infrastructure in their countries of origin. That risk can be exacerbated by exposure to destitution and overcrowded living conditions along the migration route and after entry in a host country. The ECDC says the multi-country outbreak investigation is focusing on identifying risk factors.

The agency says the limited number of cases detected so far suggests the outbreak is not likely to become a widespread event, but it has asked all European Union and European Economic Area countries whether they have identified MDR-TB cases with a similar genetic profile. While several countries say no such pattern has been identified, other countries have yet to respond.
Dec 19 ECDC Rapid Risk Assessment

Study shows azithromycin gel ineffective against Lyme disease

Topical azithromycin, an antibacterial gel that showed promise in animal studies, failed to show efficacy against Lyme disease in people but may have helped slightly in those with the tell-tale bullseye rash, according to a study yesterday in The Lancet Infectious Diseases.

The investigators assessed 995 adults bitten by ticks who were seen at 28 centers in Austria and Germany. About half of the patients applied a 10% azithromycin gel twice a day for 3 days to the tick bite, while the rest applied a placebo ointment.

The trial was stopped, however, after follow-up at 8 weeks showed 11 of 505 in azithromycin group and 11 of 490 in the placebo group had treatment failure, defined as erythema migrans (the bullseye rash) at the site of the tick bite or seroconversion. That amounts to about a 2% failure rate in both groups. In a subset of participants, however, the incidence of erythema migrans seemed to be reduced about 8% with azithromycin.

The study showed the drug to be well tolerated, which has been found for azithromycin in treating other diseases.

The authors conclude, "Inclusion of asymptomatic seroconversion into the primary efficacy analysis led to no prevention effect with topical azithromycin. Adequately powered studies assessing only erythema migrans should be considered."

An accompanying commentary by two US experts notes, "Azithromycin remains an attractive candidate for prevention of Lyme borreliosis (and perhaps of babesiosis and infection with Borrelia miyamotoi), but future studies should be designed to overcome the obstacles to conducting a definitive study."
Dec 19 Lancet Infect Dis study
Dec 19 Lancet Infect Dis commentary

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