Case series describes respiratory nerve palsy in babies born with Zika
Researchers today reported a case series of four babies with congenital Zika infections who were born with right unilateral diaphragmatic paralysis, suggesting that the virus can cause additional damage in the peripheral nervous system. A team from the Mayo Clinic and Brazil published its findings in Emerging Infectious Diseases.
Three of the babies were born in Brazil and one was born to a mother from Guatemala who immigrated to the United States. All four of the babies were girls, and all of the women who delivered them were first-time mothers who reported Zika symptoms in the first trimester of pregnancy.
All of the babies had severe microcephaly and arthrogryposis (congenital joint contracture). All died from progressive respiratory failure.
The authors noted that a study of Zika virus in macaques has suggested viral tropism to peripheral nerves. They also said Guillain Barre syndrome (GBS) is known to involve the phrenic nerve and cause diaphragmatic paralysis in adults, but the condition hasn't been reported before in newborns.
They concluded that arthrogryphosis and unilateral diaphragmatic paralysis seems to be a unique constellation of clinical findings that hasn't been reported with other congenital infections. Authors wrote though it's not clear how diaphragmatic paralysis occurs in infants, or why it's unilateral and right-sided, the damaging effects might be a unique risk factor for death in babies with congenital Zika infections, given that all four babies in the case series died within the first 3 months of life.
Jul 11 Emerg Infect Dis report
CDC team pinpoints incidence of GBS after Campylobacter infection
About 8% to 12% of GBS cases in the United States may be due to Campylobacter infection, researchers from the US Centers for Disease Control and Prevention (CDC) reported yesterday in Epidemiology and Infections.
They said that although Campylobacter infection is known to be one of the common infections that precede GBS, there are few data on the risk level.
To better pinpoint how common the complication occurs following Campylobacter illness, the scientists sifted through data collected by the CDC's Emerging Infection Program during the 2009 H1N1 vaccination campaign. They compared confirmed and probable GBS cases to noncases to gauge the risk of GBS following Campylobacter infection.
Along with the 8% to 12% of GBS cases they found linked to Campylobacter infection or diarrheal illness consistent with the disease, they estimated that 434 to 650 cases of post-diarrheal GBS occur in the United States each year and that GBS occurs in 49 of 100,000 patients who have Campylobacter illnesses.
The researchers concluded that the findings provide a useful update on the incidence of GBS following Campylobacter infection and underscore the importance of measures to prevent the infections.
Jul 10 Epidemiol Infect abstract
Study: CWD prions can convert to human prions, at least in test tubes
Chronic wasting disease (CWD) prions extracted from cervids (such as deer, elk, and moose) can convert to human prions in the lab, but not efficiently. That's the takeaway from a study published today in Emerging Infectious Diseases.
The study attempted to establish how and if CWD can be transmitted to humans if they consume infected cervid meat, which would make CWD a zoonotic illness similar to bovine spongiform encephalopathy (BSE, or "mad cow" disease). CWD has been detected in Europe, North America, and South Korea.
Previous in vivo studies conducted with squirrel monkeys have shown that CWD can cross species, but other work involving transgenic mouse models have shown the prion incapable of infecting human tissue. This study used an in vitro protein misfolding cyclic amplification to investigate the compatibility of bovine, ovine, and cervid prions with full-length, glycosylated and glycosylphosphatidylinositol-anchored human prion proteins (PrP). Prions are misfolded protein particles that can be detected in the neural tissue of infected animals.
The authors of the study said prions from infected animals can convert, but the efficiency of conversion is affected by polymorphic variation in the cervid and human PrP genes.
"Our data confirms that elk CWD prions can convert … at least in vitro," the authors conclude. "Other species affected by CWD, particularly caribou or reindeer, also seem able to convert the human PrP."
Jul 11 Emerg Infect Dis study