News Scan for Nov 09, 2015

News brief

PAHO reports almost 3,000 new chikungunya cases

Countries in the Americas and Caribbean reported 2,938 recent cases of chikungunya, bringing the outbreak total to 1,763,736, according to a Pan American Health Organization (PAHO) update from late last week.

The agency's last two updates included 2,095 and 13,476 new cases, respectively. The new numbers in the Nov 6 report bring the total this year to 616,967 suspected and confirmed cases. PAHO also reported 4 new chikungunya deaths—after reporting 5 new deaths the week before—bringing this year's fatality total to 72.

Colombia accounted for almost all the new cases. The nation, which has often had the most cases for months, reported 2,397 new cases last week, and its 2015 total now stands at 344,730. Mexico was second, with 375 cases and now has 9,395 total cases. Many countries, however, have not reported on chikungunya for weeks.

The epidemic began in December 2013 with the first locally acquired chikungunya case ever reported in the Americas, on St. Martin in the Caribbean.
Nov 6 PAHO update

Hawaii dengue cases climb to 23

The Hawaii Department of Health (HDOH) confirmed on Nov 6 that the number of locally acquired cases of dengue fever on the big island of Hawaii has increased by 8 since Nov 4, to 23.

Fifteen of the patients are Hawaiians, while 8 visitors have also been infected. All but 2 patients are adults, and all are recovering, the HDOH said in the update. Illness-onset dates range from Sep 15 to Oct 30.

"Dengue is not endemic in Hawaii. However it is intermittently imported from endemic areas by infected travelers," the HDOH said. "This is the first cluster of locally-acquired dengue fever since the 2011 outbreak on Oahu."

An FAQ published on the HDOH site said that the Aedes mosquitoes that can spread the disease are in the state and people should take steps to avoid mosquito bites and reduce their breeding grounds. The agency added, however, that the risk of contracting dengue in Hawaii is low. It said its scientists are working with the US Centers for Disease Control and Prevention to identify any new cases.
Nov 6 HDOH update
Nov 5 CIDRAP News scan on previous update

Study finds antibody drop-off 5 years after meningococcal vaccine

High numbers of adults and children vaccinated against meningococcal disease still had robust levels of antibodies to three of the four vaccine strains 5 years after vaccination, but antibody response to the "A" strain was much lower, a study today in The Pediatric Infectious Disease Journal found.

The study authors were from Kaiser Permanente and GSK, maker of the toxoid conjugate vaccine.

The researchers evaluated antibody persistence in 215 participants aged 10 to 25 years old 1, 3, and 5 years after an initial dose of either GSK's tetanus toxoid (MenACWY-TT) or diphtheria toxoid (MenACWY-DT) four-strain vaccine, but before booster dosing.

They found that at least 79.5% of the volunteers had antibody titers of 1:8 or greater for the C, W, and Y meningococcal serogroups, but only 37.5% of MenACWY-TT recipients and 44.4% of MenACWY-DT recipients had that level of antibody response for the A serogroup. The investigators also found a 5-year booster dose to be well tolerated and immunogenic.
Nov 9 Pediatr Infect Dis J study

Flu Scan for Nov 09, 2015

News brief

Study shows skin cream could boost immune response to flu vaccine

A prescription cream used to treat skin disorders applied before flu vaccine appears to increase immune response in young adults, even against drifted strains not included in the vaccine, a small study yesterday in The Lancet Infectious Diseases found.

The cream, called topical imiquimod, was previously shown to boost immunogenicity in elderly people. In the current study, Chinese researchers studied 18- to 30-year-olds for the effect of the drug, which is typically used to treat actinic keratosis, genital and anal warts, and superficial basal cell carcinoma, a minor form of skin cancer.

They enrolled 160 volunteers, 40 each to one of four groups: those receiving imiquimod cream plus a flu shot, and three control groups. The team reported a seroconversion rate of 98% in the treatment group, compared with 0, 45%, and 63% in the control groups. For the drifted H3N2 strain that became prominent last season, they noted a 75% seroconversion rate, compared with 0, 10%, and 10% in the control groups.

"Topical application of imiquimod before intradermal trivalent influenza vaccine significantly improved immunogenicity against the vaccine influenza strains in young healthy individuals and increased immunogenicity against the non-vaccine strains, especially the antigenically drifted H3N2 strain of 2015, which was not included in the 2013-14 recommended vaccine," the researchers reported.
Nov 8 Lancet Infect Dis study
Nov 8 Lancet Infect Dis commentary on the study

Skunks shown to be hit hard by H7N9, shed a lot of viruses

Of three mammal species tested, skunks had the highest disease burden and shed the most viruses after being infected with H7N9 avian flu, according to a new study in Virology.

Scientists from the US Department of Agriculture, the Colorado State University, and University of Queensland in Australia experimentally infected striped skunks, cottontail rabbits, and raccoons with H7N9. They found that the skunks had the highest disease burden, followed by raccoons and rabbits. They also noted that skunks produced the highest levels of viral shedding, followed by the rabbits and raccoons.

They said the study shows that mammals may play a role in H7N9 disease epidemiology.

They conclude, "Mammals should be accounted for in biosecurity plans associated with H7N9 and their presence in wet [live-animal] markets, dependent on species, could lead to increased transmission among interspecific species aggregations and may also pose an elevated zoonotic disease risk to visitors and workers of such markets."
Nov 6 Virology study