Stephanie Brown
Instrutor: Evelyn Galvez
Bio Lab 1615
Article Outline: A Focus of Dogs and Rickettsia Massiliae-Infected Rhipicephalus
sanguineus in California
Introduction
This article discusses how Rickettsia Massiliae affects humans and dogs when
infected. It also talks about how some of the reports of spotted fever may be R. massiliae
in humans. R. massiliae is tested and found to be present in ticks. They discuss how R.
massiliae and it association with different Rhipicephalus spp extended to different
countries including Mediterranean, Africa, and Argentina. It is unknown if the specific
genetic types of R. massiiae have adapted to different tick vectors, animal hosts, and their
potential to cause febrile illness. They report the results of an investigation that was
triggered by sick dogs living on a property in Los Angeles County, CA. It also discusses
how serologic evidence for canine expose to Rickettsia, and anti-rickettsial antibodies on
tick feeding and circulation demonstrate a lack of a cure.
Materials
In August 2007 and March 2008, the Los Angeles County Veterinary Public
Health and Rabies Control Program was notified of sick dogs living at on the same
property. The 2 sick dogs that lived together were suspected to have Rocky Mountain
spotted fever, a rare condition in the area. The 2 dogs where found seropositive to spotted
fever group rickettsiae and had heavy infestation of brown dog tick RH. sanguineus.
Blood treated with EDTA and serum was used to test both the sick dogs and 2 other dogs
living in the same house that were said to be healthy. Ticks from the same property and
the dogs were also collected and tested. The owner was provided information on tick
control and prevention measures. The testing included electrophoresis and Western
blotting and used suspensions of purified rickettsiae diluted in water to concentrate;
serum samples made of antigens of Rickettsia-infected nuclear fractions collected as a
by-product of the rickettsial purification of infected cells that were frozen and then
thawed and then fixed in acetone and were screened by macro immunofluorescence
testing; protein gel was used to measure protein concentration by using bicinchoninic
acid and protein; and PCR testing extracted DNA from organ tissues to complete
sequence analysis to determine the different kinds of tick it being tested.
Results
The results include the out come of using preventative care and treatments
provided by veterinarian clinics. The symptoms that the dogs experienced before, during,
and after treatment were provided. It also includes the testing information and interrupts
what was found on the ticks. It gives detail about each specimen found on the dogs and
on the ticks. They found PCR-positive ticks on each of the four dogs tested. They also
included a table displaying the “Detection of antibodies to spotted fever group Rickettsia
antigens in canine sera, California” providing the date serum was collected, type of
Rickettsia antigen and number of antibodies for each of the four dogs tested. Also results
for the Western Blotting and serum cross-absorption are given in detail with an included
diagram of the gel testing.
Discussion
In the discussion there is a comparison of the R. massiliae and spotted fever.
Tells how the R. massiliae may be transmitted through different rickettsial species and
ticks. Also how dogs may become infected. The effects on humans bitten by ticks are
provided. Information on how to prevent tick exposure is given.
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