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