China adds two more cases to H7N9 total
China reported two more H7N9 avian influenza cases, including the season's second case detected in Beijing, according to official sources and state media.
The illness reported from Beijing appears to be another imported case, this time from Liaoning province, according to a state media report translated and posted by FluTrackers, an infectious disease news message board. The patient is a 48-year-old man who got sick on Jan 31 and was transferred on Feb 8 to a hospital in Beijing. The report said he had a history of contact with live poultry.
The other new case involves a 23-year-old woman whose illness was detected in Yunnan province, according to a provincial health department statement translated and posted by FluTrackers. The report said the woman had traveled from Jiangxi province and that she is part of a mother-daughter cluster, both of whom had live bird contact. The case appears to be related to another recent imported case reported by Yunnan province, a 3-year-old girl who was also from Jiangxi province, and died from her illness.
China is in its fifth and biggest wave of H7N9 activity since the virus was first detected in humans in early 2013. So far this season the country has reported at least 351 cases.
Feb 15 FluTrackers thread on Beijing case
Feb 15 FluTrackers thread on Yunnan province case
Study reveals more on Zika persistence in body fluids
Researchers who monitored Zika virus persistence in different body fluids in a group of newly infected patients from Puerto Rico found that viral RNA lingers in blood longer than dengue and other flaviviruses and that for men, Zika RNA usually cleared from semen after about 3 months. Researchers from the US Centers for Disease Control and Prevention (CDC) and Puerto Rico published their findings yesterday in the New England Journal of Medicine.
The team examined samples from 150 participants, including 55 men. Most were recruited during the first week of symptom onset. Researchers collected serum, urine, saliva, semen, and vaginal secretions weekly for the first month after lab-confirmed Zika diagnosis. Then they repeated sample collection at months 2, 4, and 6. All of the specimens were tested by reverse-transcriptase polymerase chain reaction (RT-PCR), and serum was tested by IgM assay. Patients who still tested positive for any type of specimen at week 4 underwent biweekly collection until results were negative.
Zika RNA typically cleared serum within a median time of 14 days, with a 95th percentile time of 54 days, urine 8 and 39 days, respectively, and semen in 34 and 81 days, respectively. Few of the participants had detectable Zika in saliva or vaginal secretions.
Most of the participants no longer had Zika RNA in blood at 8 weeks, which seems to suggest that the risk of intrauterine transmission in Zika-infected women who are trying to conceive at the end of the CDC's at least 8-week recommended waiting period is small.
Few men in the study had detectable Zika RNA past 3 months, with the maximum time at 125 days. The clearance times were shorter than the CDC's recommended 6 months of condom use or abstinence from sex for men with possible Zika exposure.
The group said the findings are preliminary and more study is needed, but the prolonged clearance in blood may have implications for diagnosis and prevention.
Feb 14 N Engl J Med abstract
WHO updates yellow fever vaccine recommendations
Yesterday the World Health Organization (WHO) updated yellow fever vaccination recommendations for travelers going to Brazil. As yellow fever continues to march towards Brazil's east coast, the WHO advises travelers to several of the country's regions get vaccinated prior to traveling.
Three recommendations detail risk areas in three states: Bahia, Espirito Santo, and Rio de Janiero. The WHO says travel to most regions of those states should be accompanied with yellow fever vaccination. According to the agency, there is no evidence of yellow fever virus transmission in the states' large metropolitan areas, including such as Rio de Janeiro, San Salvador, and Sao Paulo.
The current outbreak began in January in Minas Gerais state and Espirito Santo state. As of Feb 2, local news sources estimated that there were more than 700 cases of the mosquito-borne disease in Brazil.
The WHO recommends vaccination against yellow fever at least 10 days prior to visiting affected regions. In light of the upcoming Carnival celebrations, the WHO also recommends that travelers take precautions to prevent mosquito bites, and be aware of symptoms of yellow fever.
Feb 13 WHO update
Feb 2 CIDRAP news story "Surge of yellow fever in Brazil raises alarms"
Malaria vaccine offers highest level of protection in human trial
A malaria vaccine was completely successful in preventing the disease in 35 humans, according to a new study published today in Nature. There were also no severe side effects reported.
The vaccine candidate, PfSPZ, uses infectious Plasmodium falciparum sporozites (PfSPZ) derived from the parasite that causes malaria to illicit an immune response in recipients. This is the first human trial of the vaccine.
According to the authors, when PfSPZ was delivered in 4-week intervals, the lower doses only protected some of the participants against infection, but the highest dose achieved 100% protection (in nine participants) for at least 10 weeks after the last dose. High doses given 5 days apart protected 65% of participants. The same high dose delivered at a shorter time period (three doses at 5-day intervals) protected five out of eight individuals (63%).
"Although this 10-day regimen was less protective than the 56-day regimen (63% versus 100%), we hypothesize that increasing numbers of PfSPZ per dose will increase protective efficacy to 100% with the 10-day regimen," the authors said, noting that a shorter duration between immunizations would benefit recipients and increase use of the vaccine.
Feb 15 Nature study