Exploring The Effect Climate Factors Have On Cyathostomin Populations In The United States
Date
2022-05
Authors
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Publisher
University of Delaware
Abstract
Cyathostomins (small strongyles) are parasitic worms found in the equine
digestive system (caecum and colon). There are fifty known species with little
knowledge about each individual one. They have a simple lifecycle during which
eggs develop into infective larvae on pasture. While transitioning, the larvae are
exposed to multiple climatic factors such as temperature, precipitation, and
humidity. This study’s goal was to profile cyathostomin communities from across
the United States to determine which climate factors significantly influence the
survival of different species. Sample locations were categorized based on USDA
Zones. Zones 3-10 make up the contiguous United States and are separated by
10℉ increments. Horse owner’s samples were collected from each zone via the
Equine Microbiome Project and returned, DNA was extracted, the 5.8SITS genes
were amplified and sequenced. There were 186 samples included in the final
dataset and analyzed using QIIME II and R studio following a presence absence
method. Multiple statistical tests were used, including ANOVA and a Spearman’s
correlation. Multiple species (Cyathostomum catinatum, Cylicocyclus nassatus,
Cylicostephanus goldi, Cylicostephanus calicatus, Cylicocyclus insigne,
Cylicocyclus ashworthi, Caythostomum pateratum, and Cronocyclus labiatus)
were found to be prevalent across all climate zones seemingly unaffected by the
climate factors tested. Other species (Cylicostephanus mintus, Cylicostephanus
longbursatus, Cylicocyclus ultrajectinus, Cylicocyclus radiatus) were sensitive to
climate factors. Of the factors tested, cyathostomin species were shown to be
significantly sensitive to humidity and zone rather than temperature, precipitation,
or season. Identifying species-specific climate factors that significantly effect a
cyathostomin’s ability to be successful can help specify control methods in the
future.
Description
Keywords
Parasites, Equine science, Climate factors