Experts theorize why Brazil had fewer microcephaly cases in 2016 than 2015
A new letter published in the New England Journal of Medicine attempts to explain why Brazil saw fewer babies born with microcephaly in 2016 as compared to 2015, despite more suspected Zika infections. The authors suggest that 2016's second wave of Zika infections could have actually been another flavivirus, such as chikungunya.
Using data from two national databases, experts from Brazil and the World Health Organization (WHO) showed that in 2015 a spike in Guillain-Barre syndrome (GBS) was followed 6 months later with a spike in microcephaly cases. Zika infection has been linked to both diseases. But in 2016, a spike in GBS was not followed by a subsequent rise in microcephaly numbers. The authors suggest that chikungunya —not Zika—was causing the GBS in 2016, and Brazil only experienced a true Zika outbreak in the previous year.
The authors posited two other possibilities for the lack of microcephaly cases in 2016: the women in 2015 suffered an unknown co-infection or co-factor that led them to have babies with microcephaly, or the fear of microcephaly and Zika infection led to more abortions and delayed pregnancies. But birth registry data are not yet complete enough to determine whether birth rates fell or abortion rates increased in 2016.
"Among these hypotheses, the first seems to be the most plausible — that is, both ZIKV and chikungunya viruses are important causes of GBS, but among the arboviruses circulating in Brazil, only ZIKV causes microcephaly and other neurologic disorders after infection during pregnancy," the authors conclude.
Mar 29 N Engl J Med letter
MERS evidence found in camels from more African countries
Camels sampled in Burkina Faso, Ethiopia, and Morocco show evidence of exposure to MERS, and scientists also see seropositivity patterns based on location, type of camel herd, and density of the herd. Researchers reported their findings today in the latest issue of Eurosurveillance.
Camels from Ethiopia—a main exporter of camels to the Arabian Peninsula—are already known to test positive for Middle East respiratory syndrome coronavirus (MERS-CoV) RNA, but the findings for Burkina Faso and Morocco are the first and add to the growing of list of countries in north, west, and east Africa where the virus is thought to circulate in the animals.
In the new study, researchers obtained blood and nasal samples from 1,500 camels in a variety of settings in the three countries in February and March of 2015. They found a relatively high rate of MERS-CoV RNA in samples from Ethiopian camels (up to 15.7%), followed by Burkina Faso (12%) and Morocco (7.6%).
MERS-CoV RNA detection rates were higher for camels that were raised for milk or meat, in younger animals, and large- and medium-sized herds. Research said the levels in younger camels might be higher, because they may be more susceptible due to lack of previous exposure, and that the female camels in milking herds might be re-exposed by the younger camels. Also, they noted camels in higher-density settings, compared to those used for transport in which the animals are separated from the herd, could amplify transmission when the virus is brought in from other sources.
They said genetic analysis of MERS-CoV from camels from the three countries is needed to better understand how the virus evolves in African camels.
Mar 30 Eurosurveill report
In other MERS developments, Saudi Arabia's Ministry of Health (MOH) today reported one more illness, involving a 63-year-old Saudi man from Abqiq in the east central part of the country who had direct contact with camels before he got sick. The case continues a slow but steady stream of MERS-CoV cases reported from Saudi Arabia.
The MOH said in its daily update that the man is hospitalized in critical condition. Direct or even indirect contact with camels is a known risk factor.
Since MERS-CoV was first detected in humans in 2012, Saudi Arabia has now reported 1,583 cases, including 659 deaths. Eight people are still being treated.
Mar 30 Saudi MOH statement
Six more people sick from contaminated soy nut butter
Since the last update on Mar 21, the Centers for Disease Control and Prevention (CDC) said today that six more people from four states have become ill after eating soy nut butter contaminated with Shiga toxin–producing Escherichia coli.
So far, 29 people have become infected with the outbreak strains, which were linked to I.M. Healthy SoyNut Butter. Twelve of the people, including 2 of the recent cases, have been hospitalized for complications; 9 people have developed hemolytic uremic syndrome, a type of kidney failure. There have been no deaths reported. Almost all cases (24, or 83%) have been in children.
Florida, Illinois, and Massachusetts each reported new cases in the last week, bringing the total number of states reporting cases to 12.
I.M. Healthy recalled its nut butter on Mar 7 and has expanded the recall to include other products made with potentially contaminated ingredients. The investigation is ongoing, and the CDC warned that, "Illnesses that occurred after March 7, 2017, might not yet be reported due to the time it takes between when a person becomes ill and when the illness is reported. This takes an average of 2 to 3 weeks."
Mar 30 CDC update
Study shows potential for 2-dose dengue vaccine schedule
Interim results from a phase 2 study of Takeda's tetravalent dengue vaccine, which assessed different dosing schedules, suggests that two doses given 3 months apart should be given in a phase 3 trial to assess efficacy, an international team of researchers reported today in an early online edition of The Lancet Infectious Diseases.
The vaccine combines an attenuated dengue type 2 virus strain with three chimeric viruses that contain pre-membrane and envelope protein genes of dengue type 1, 3, and 4 on the attenuated dengue type 2 genome backbone.
The trial is underway among 1,794 children ages 2 to 17 years old in three dengue-endemic countries: Dominican Republic, Panama, and the Philippines. They found that the vaccine was safe and immunogenic, despite any previous dengue exposure, and that a second dose enhanced immunity markers against dengue types 3 and 4 in kids who were seronegative before vaccination.
In a commentary in the same issue, Annelies Wilder-Smith, MD, PhD, with the school of medicine at Nanyang Technological University in Singapore, wrote that the currently approved vaccine made by Sanofi is a welcome step, but its use is made more complex by varying efficacy estimates and the need to be given in three doses 6 months apart.
She said the scientific community is eagerly watching trials of second-generation dengue vaccines. Given that Takeda's vaccine is designed to trigger both humoral and cellular immune response, Wilder-Smith said that experts are also eager to see if the immunogenicity data from the phase 2 trial of the Takeda vaccine translates to protection and if efficacy is affected by serotype, age, and previous exposure.
Mar 29 Lancet Infect Dis abstract
Mar 29 Lancet Infect Dis commentary
No safety signals seen for HPV vaccine in pregnancy
A study of Danish women who inadvertently received quadrivalent (four-strain) human papillomavirus (HPV) vaccine during early pregnancy found that the immunization wasn't associated with a significantly higher risk of adverse pregnancy outcomes, according to a study today in the New England Journal of Medicine.
They based their findings on a matched analysis of Danish women exposed to HPV vaccine October 2006 through November 2013 as identified through national registers. They compared results from 1,665 exposed pregnancies with those of 6,660 unexposed pregnancies.
The numbers of spontaneous abortions, preterm births, infants with low birth weights, infants who were small for gestational age, and stillbirths were not higher in the vaccinated cohorts, though the number of stillbirths was small.
In an editorial in the same issue, Kathryn Edwards, MD, with the division of infectious diseases at Vanderbilt University School of Medicine in Nashville, Tenn., wrote that the data are encouraging and strongly support the safety of HPV vaccine if inadvertently given in pregnancy, findings that are in line with safety reports about HPV vaccination in nonpregnant women.
Vaccines specifically used among pregnant women need to be carefully studied in prelicensing trials to ensure safety, but in the case of HPV and other vaccines not targeted to the group but sometimes inadvertently given, she added that postmarketing evaluations—such as today's well-designed study—are important.
Mar 30 N Engl J Med abstract
Mar 30 N Engl J Med editorial
Somalia cholera outbreak spreads to inaccessible areas
The number of cholera cases this year in Somalia—a country grappling with political conflict and on the brink of another famine—has already passed the total number of cases reported for all of 2016, the WHO Eastern Mediterranean Regional Office (EMRO) said in a recent update.
So far 17,211 cases, including 388 deaths, have been reported, quadruple the number reported for the same time period in 2016. Though outbreaks have been controlled for some locations, many of the recently reported cases are from inaccessible villages in neighboring Bay and Gedo regions in the south. The country's health ministry has sent more health workers to Bay region.
Conditions in Somalia have put nearly half of the country's 12.3 million people in need of humanitarian assistance, with 5.5 million of them at risk for waterborne diseases. The WHO warned that hundreds of thousands of people are on the move in search of food, water, shelter, and medical care.
Mar 26 WHO EMRO update