Flu Scan for Mar 23, 2016

News brief

Global flu activity remains high, with increased H1N1, flu B in Northern Hemisphere

Flu levels in Europe and North America continued to rise, with high but stable activity noted in northern Asia and China, the World Health Organization (WHO) said in a Mar 21 update.

The 2009 H1N1 virus is the predominant strain worldwide, though detections of influenza B have increased in Europe and northern Asia.

Flu levels due to H1N1 continued to rise in the United States and Canada, while Mexico reported above-threshold rates of acute respiratory infections and pneumonia.

Europe continues to report high H1N1 activity, with increased flu B detections in northern and southwestern regions. The flu season in Eastern Europe appears to have peaked, the WHO said.

Flu levels remain high in northern temperate areas of Asia, with H1N1 predominating and increased flu B detections. Mongolia reported rises in flu-related pneumonia and deaths, and China detected increased levels of flulike illness. Southeast Asia saw ongoing levels of H1N1 and flu B detections.

Flu activity in western Asia is low, with the exception of high severe illness reported in Kazakhstan, the WHO said. Flu levels in the tropical Americas remain at low levels, with the exception of severe illness reported in Jamaica.

Globally, influenza A made up 74.2% of flu detections in recent weeks, and of the subtyped samples, 87.3% were the 2009 H1N1 virus, and 12.7% were H3N2. Of the subtyped flu B samples, only 25.2% were from the Yamagata lineage, the B strain used in this season's trivalent Northern Hemisphere flu vaccines.
Mar 21 WHO update

Study shows progressive H5N1 genetic diversity and adaptation to humans

An analysis of H5N1 avian flu viruses in Egypt showed that an endemic clade has undergone rapid and persistent evolution in ways that may increase its transmissibility to humans, according to a study published yesterday in Virology Journal.

Researchers from the United Nations Food and Agriculture Organization (FAO) analyzed genetic mutations in H5N1 viruses, including the clade that emerged in poultry in 2006 and was stable through 2009, two clusters from a variant clade detected from 2007 to 2011, and an endemic clade that emerged in 2008 and has since become dominant.

Most of the hemagglutinin sequences analyzed (224 of 368) were from the 2008 endemic clade, which has undergone wide geographic distribution throughout Egypt, resulting in increased live-bird-market detections.

The endemic cluster demonstrated a high and persistent mutation rate over 6 years. The researchers found that 57% of endemic clade viruses had a triple mutation at the receptor binding site, a characteristic that was observed in all endemic clade viruses from 2012 to 2014 and may significantly affect transmissibility of H5N1 between birds and humans.

Approximately 60% of viruses belonging to the endemic clade also had four mutations at antigenic sites, suggesting significant drift since 2008, the researchers said.

Persistence of the endemic clade, its increased binding affinity in human cells, and the emergence of a new H5N1 endemic clade cluster in 2015 may be the result of poor avian vaccination practices and wide geographic distribution of the virus in Egypt, the authors said.
Mar 22 Virol J study

News Scan for Mar 23, 2016

News brief

Brazil microcephaly total grows; WHO unveils interim lab guidance

In Zika virus developments today, Brazil's health ministry reported 273 more suspected microcephaly cases and the World Health Organization (WHO) released interim guidance on lab testing for Zika infection.

In a weekly update, Brazilian officials said that the number of new cases pushes the overall number of suspected cases still under investigation to 4,293, according to a statement translated and posted by Avian Flu Diary, an infectious disease news blog.

The ministry said 53 more microcephaly cases were confirmed last week, raising that total to 907. In addition, investigators ruled out 128 additional earlier reported suspected cases.

At a WHO media briefing yesterday, Anthony Costello, MD, director of the WHO's maternal, newborn, child, and adolescent health department, said most of the microcephaly cases are from northeastern Brazil and that about 39% of suspected cases are confirmed. At that rate he estimated that the number of microcephaly cases could reach about 2,500 by the end of the year, according to currently available data.
Mar 23 Avian Flu Diary post

The WHO, meanwhile, said its 5-page interim guidance document on Zika testing was developed by an international expert group that met by teleconference on Feb 18. The group said during outbreaks, especially where transmission is widespread, testing every suspected case will not be cost effective and that certain groups should be prioritized.

They include pregnant women with a history of travel to affected areas or who had sexual contact with a confirmed or probable case, patients with suspected neurologic disorders, those who had sexual contact with a suspected or confirmed case, pregnant women whose fetuses have brain abnormalities, babies in affected areas born with brain defects or to women with a history of travel to affected areas, infants born to infected mothers (especially if breastfeeding), and stillbirths or miscarriages in women who lived in or traveled to Zika-hit areas.
Mar 23 WHO interim lab testing guidance

Twelve sepsis deaths noted in Guadeloupe chikungunya outbreak

Scientists from the Guadeloupe island group, writing in Emerging Infectious Diseases yesterday, reported 25 cases of severe sepsis and 12 associated deaths likely attributable to chikungunya infection during a 2014 outbreak.

Of 110 non-pregnant adults hospitalized with chikungunya in 2014, 42 had infections resulting in failure of one or more organs or intensive care unit admission. More than half of patients with severe illness (25, or 59.5%) progressed to sepsis or septic shock, and 12 died.

Patients with severe infections were more likely to have acute cardiac failure and organ dysfunction, in addition to higher white blood cell counts and higher enzyme levels indicating tissue damage compared with patients who had less severe illnesses.

No cause other than chikungunya infection was identified in the 25 patients who progressed to severe sepsis or septic shock. Septic patients were more likely to have presented with cardiac, respiratory, and renal signs and symptoms upon admission, the researchers said. The mortality rate was much higher among septic patients (48%) than in patients with less severe illness (3%).

The researchers noted the rarity of septic shock triggered by a viral illness, saying that sepsis could be a significant complication of severe chikungunya infection. Guadeloupe experienced a chikungunya outbreak from February to November 2014, during which approximately 40% of the islands' population were infected, or 160,000 people.
Mar 22 Emerg Infect Dis study

Study notes difference in bacteria strains, clinical disease in US, European Lyme

Strains of Borrelia burgdorferi—the bacterium that causes Lyme disease—vary from Europe to the United States and cause more severe disease in US cases, according to a study yesterday in Emerging Infectious Diseases.

Slovenian and US researchers analyzed B burgdorferi sensu stricto isolates from European and US patients who had the erythema migrans rash, which is characteristic of Lyme, though not all patients develop it. They studied 29 Slovenian and 91 US samples. Genotyping of the isolates revealed two distinct genotypes.

In addition, the investigators found that clinical features of the Slovenian patients were similar to infection with B afzelii or B garinii, the other two Borrelia species that cause Lyme disease in Europe. B burgdorferi strains from the United States, in comparison, were associated with more severe disease.

The team also found that US B burgdorferi strains induced blood cells to secrete higher levels of cytokines and chemokines associated with innate and Th1-adaptive immune responses, whereas European strains induced greater Th17-associated responses.
Mar 22 Emerg Infect Dis study