News Scan for Feb 01, 2018

Yellow fever in Brazil
Lone star ticks not Lyme spreaders
Seoul virus in US, Canada
Malaria, yellow fever travel notices

More yellow fever cases, deaths reported in Brazil

A new report from Brazil's Ministry of Health showed a steady rise in the number of yellow fever cases confirmed and suspected since an update posted last week. There are now 213 confirmed cases, 83 more than last week, and 1,080 suspected cases, an increase of 479 since the previous report.

There have been a total of 81 deaths so far between Jul 1, 2017 and Jan 30, 2018, the Ministry of Health said. Between July of 2016 and January of 2017, Brazil reported a total of 468 confirmed yellow fever cases, including 147 deaths.

Yellow fever cases tend to spike during the rainy, spring months in Brazil. There is still no evidence that urban Aedes aegypti mosquito populations are transmitting the virus. Instead, the Ministry of Health said all human cases remain caused by sylvatic spillover. The information was translated and posted on ProMED Mail, the online reporting system of the International Society for Infectious Diseases.

As reported last week, a vaccination campaign is set to launch this month in some of Brazil's most populous states, using both standard and fractional doses of the yellow fever vaccine. Both vaccines offer 99% protection against the virus within 1 month of administration.
Jan 30 ProMED Mail post
Jan 24 CIDRAP News story "Yellow fever case counts jump in Brazil"


Lone star ticks off the hook for transmitting Lyme disease

A review of 30 years' worth of literature shows that the lone star tick is not capable of spreading the bacteria that causes Lyme disease to humans. The review was published yesterday in the Journal of Medical Entomology.

Led byEllen Stromdahl, BCE, an entomologist at the US Army Public Health Center, the review of 60 published scientific journal articles failed to produce evidence that the tick (Amblyomma americanum) can spread Borrelia burgdorferi, the bacterium that causes Lyme disease. In fact, there is evidence that the tick's saliva destroys Borrelia burgdorferi.

"Lone star tick saliva is a very effective barrier against B. burgdorferi—it literally explodes them," said Graham Hickling, PhD, a tick researcher from the University of Tennessee who contributed to the review in an interview with Entomology Today. "Lone star ticks are constantly being exposed to B. burgdorferi as they feed on infected animals, but the bacteria species has never been cultured from a Lone Star tick in a lab. However, it has been cultured from rodents and blacklegged ticks in the Southeast."

The authors said that early literature detecting B. burgdorferi in lone star ticks used methods that were not Borrelia species-specific, and any spirochetes that were detected were likely other species.
Jan 31 J Med Entomol study
Jan 31 Entomology Today


First Seoul virus outbreak in United States and Canada described

2017 brought the first Seoul virus outbreak to the United States and Canada, and emphasized the need for proper rodent handling, according to a report today in Morbidity and Mortality Weekly Report (MMWR).

In December of 2016, a Wisconsin resident was hospitalized with fever and leukopenia, among other symptoms. The person owned an in-home rat breeding facility. Because of his or her contact with rats, the patient was tested for hantaviruses, including Seoul virus. The Centers for Disease Control and Prevention (CDC) confirmed the presence of Seoul virus in January of 2017, and an investigation was launched to identify additional human and rat infections.

By March of 2017, 31 US ratteries with human and/or rat Seoul virus infections were discovered in 11 states, including 6 that exchanged rats with Canadian ratteries. A total of 17 people were infected with Seoul virus, with 8 becoming ill and 3 hospitalized. All cases recovered fully.

Seoul virus is a hantavirus in the Bunyaviridae family, found most commonly in the Norway rat.

"Pet rat owners should be aware of the potential for Seoul virus infection," the authors of the report write. "To keep themselves and their pets healthy, all persons with rodent contact should avoid bites or scratches and practice good hand hygiene, especially children and persons with compromised immune systems."
Feb 2 MMWR report


CDC posts travel notices for malaria in Brazil, yellow fever in Nigeria

The CDC posted two new travel notices, one a level 2 alert warning of a malaria outbreak in Brazil's Bahia state and the other a level 1 alert that relates to yellow fever activity in Nigeria.

In Brazil, the mosquitoes that spread malaria are present in Bahia state in the eastern part of the country, but the disease isn't usually found there. The CDC said the outbreak in the town of Wenceslau Guimaraes probably began with an infected person who traveled from Para state, in northern Brazil, where the disease is known to spread. The CDC's level 2 precaution urges travelers to practice enhanced precautions, specifically for travelers to the affected town to take antimalarial medication.

Meanwhile, the notice for Nigeria relates to an outbreak that has been under way since September 2017, with lab-confirmed cases reported in at least seven states. Vaccination campaigns are ongoing in the country. The CDC's level 1 watch urges travelers to practice usual precautions, and the CDC recommends anyone 9 months or older who will travel to any part of Nigeria to be vaccinated against yellow fever.
Jan 31 CDC travel notice on malaria in Brazil
Jan 30 CDC travel notice on yellow fever in Nigeria

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