News Scan for Mar 19, 2020

Ticks lurk in leaf piles
Low-path H7N3 avian flu in North Carolina

Study: To avoid ticks, don't dump fall leaves on wooded edge of lawn

Raking or blowing fall leaves on a lawn's border with a wooded area can create the ideal habitat for blacklegged ticks to thrive and spread disease the next spring, according to a study yesterday in the Journal of Medical Entomology.

Blacklegged (deer) ticks are the main cause of Lyme disease in the eastern United States, spread human babesiosis and human granulocytic anaplasmosis, and may transmit emerging diseases such as Powassan encephalitis.

The researchers set up test plots in three residential lawns in Monmouth County, New Jersey, in fall 2017 and 2018, with some plots near the forest edge and some deeper inside it. They allowed leaves to accumulate naturally in some edge plots while periodically raking or blowing more leaves into others, causing accumulations two or three times deeper than in the natural edge and forest plots.

The next spring, they used drag sampling to compare the number of juvenile blacklegged and lone star ticks in the plots. They found that blacklegged tick numbers were triple in the managed plots compared with the natural ones, while lone star tick numbers were inconsistent. Lone star ticks spread human monocytic ehrlichiosis and may transmit other diseases, as well.

The data suggest that residents may have a significantly higher risk of coming into contact with blacklegged ticks in raked or blown leaf piles at the edges of their own lawn than in natural forest edges, the authors said. Deep, artificially created piles at a yard's edge can create a tick-friendly habitat of elevated humidity, reduced temperatures, and protection from the winter elements, the researchers noted.

They recommend that homeowners use city or county leaf disposal services, ask landscaping contractors to dispose of the leaves offsite or move them away from frequently used areas, or speed leaf decomposition with mulching in areas with low leaf accumulation. "The development of strategies to manage vector tick populations in order to minimize human-tick encounters remains a public health priority," they wrote.
Mar 18 J Med Entomol article
Mar 18 Entomological Society of America news release


Avian flu outbreaks strike poultry in North Carolina, the Philippines

The US Department of Agriculture has reported low-pathogenic H7N3 avian flu outbreaks at three turkey farms in North Carolina, according to a notification from the World Organization for Animal Health (OIE).

The virus was found during routine surveillance for H5 and H7 avian flu, and the only clinical signs were a slight drop in egg production in a breeder flock. The outbreaks began on Mar 10, affecting two turkey meat farms in Union County, near Charlotte, and a turkey breeding farm in neighboring Anson County. Five other farms have been quarantined and sampled, and results are pending.

Culling with the foam method and disposal are planned for the 90,200 turkeys at the three affected farms. So far, the source of the virus hasn't been determined.

Low-pathogenic H7N3 has been detected in US poultry before, such as in California turkeys in 2018.
Mar 16 OIE report on H7N3 in North Carolina

Elsewhere, the Philippines reported another highly pathogenic H5N6 outbreak, which affected a backyard quail farm, according to a separate OIE report. The event began on Mar 6 in Nueva Ecija province. The virus killed 3,000 of 15,000 birds, and the rest were culled to control the spread of the virus. Though the source of the outbreak isn't known, the report said there were wild birds near the area.

The Philippines reported its first outbreak involving the strain in 2017.
Mar 17 OIE report on H5N6 in the Philippines

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