News Scan for Sep 25, 2014

New MERS case, death
;
MERS-CoV in camels
;
Dengue control in Brazil
;

Saudi Arabia confirms MERS case, death; WHO panel meets

Saudi Arabia's Ministry of Health (MOH) confirmed a new MERS-CoV infection today—the 10th since Sep 8—as well as the death of a recently reported case-patient.

The new case is in a 60-year-old Saudi from Riyadh who had unspecified preexisting disease. He is hospitalized in an intensive care unit (ICU) and is not a healthcare worker nor did he have any recent exposure to animals, the MOH said.

The patient who died was a 76-year-old man from Najran. His MERS-CoV (Middle East respiratory syndrome coronavirus) illness was announced by the MOH on Sep 15. At the time, he was in an ICU, had preexisting disease, and did not report recent contact with animals.

Today's report brings the number of Saudi MERS cases to 752, of which 318 have been fatal.
Sep 25 MOH report

In a related development, the World Health Organization's (WHO's) Emergency Committee on MERS-CoV began its seventh meeting today, the WHO said in an e-mail message to journalists. The committee, convening electronically, will hear reports from affected countries and discuss recent developments. The meeting will end next week.

At its last meeting, on Jun 16, the panel concluded that the MERS situation did not meet the criteria for a public health emergency of international concern.

 

Study shows human MERS-CoV can sicken camels

Camels that were deliberately infected with a human isolate of MERS-CoV became mildly ill and shed large amounts of the virus, supporting the view that camels are a likely source of human MERS cases, according to a study yesterday in Emerging Infectious Diseases.

Epidemiologic, serologic, and genetic evidence suggests that camels can pass MERS-CoV to humans, but whether they are the virus's primary reservoir is still debated, note the study authors, who are from Colorado State University and the National Institute of Allergy and Infectious Diseases (NIAID) lab in Hamilton, Mont.

The researchers inoculated three young adult camels (which did not carry MERS-CoV antibodies) with a human MERS-CoV isolate via the eyes, nose, and throat. All three animals showed mild signs of illness and shed large amounts of virus in their nasal secretions for up to 7 days after infection, according to the report. Also, viral RNA was shed for up to 35 days.

The authors found no evidence of the virus in the camels' urine or feces, which matched up with field observations, they said. Histopathologic examination showed that the respiratory epithelium in the nasal turbinates was the predominant site of MERS-CoV replication.

"The pattern of shedding and propensity for the upper respiratory tract infection in dromedary camels may help explain the lack of systemic illness among naturally infected camels and the means of efficient camel-to-camel and camel-to-human transmission," the report says.

An NIAID press release says the authors theorize that vaccinating camels could reduce the risk of MERS-CoV transmission to people and other camels and notes that NIAID and others are supporting research on MERS-CoV vaccines for people and camels.
Sep 24 Emerg Infect Dis report
Sep 24 NIAID press release

 

Brazil releases dengue-fighting mosquitoes

Brazilian scientists have released thousands of Wolbachia-infected Aedes aegypti mosquitoes in an attempt to tame the spread of dengue fever, a mosquito-borne disease of humans, which re-emerged in the country in 1981 after a 20-year lull and caused some 7 million illnesses over the following 30 years, the BBC reported today.

Wolbachia is an intracellular bacterium that "acts like a vaccine" for dengue-carrying mosquitoes in that it stops the dengue virus from multiplying in the insect's body, according to the story. The organism also interferes with reproduction in mosquitoes. Eggs fertilized by Wolbachia-contaminated male mosquitoes do not turn into larvae, and if a female mosquito is contaminated, all her future generations will also carry the bacterium.

The sum result is that mosquitoes infected with Wolbachia,which is not transmissible to humans or animals, multiply and become dominant, with the benefit to humans that those mosquitoes can't transmit dengue.

The plan is to release 10,000 contaminated mosquitoes each month for 4 months. The first release is in a northern part of Rio de Janeiro. Studies and an evaluation of the project are scheduled for 2016. Similar initiatives are under way in Australia, where research on the dengue control method began in 2008, and in Vietnam and Indonesia.

Dengue fever typically causes fever, headache, and muscle and joint pain. Some cases turn into dengue hemorrhagic fever, a much more serious illness that can be fatal.
Sep 25 BBC story

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