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Group 2
Lizards and Lyme disease risk
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Group
- Carvalho, Rodrigo Mazzei; Federal University of Bahia, Biology Institute, Brazil
- Castro, Danielle; University of São Paulo, School of Public Health, Brazil
- Erazo, Diana; BIOMAC, Universidad de los Andes, Colombia
- Gaiarsa, Marilia Palumbo; University of São Paulo, Ecology Department, Brazil
- Prist, Paula Ribeiro; University of São Paulo, Ecology Department, Brazil
- Rodriguez Carrillo, Luisa Fernanda; National University of Colombia, Mathematics Dept., Colombia
Assignment
The Lyme disease is caused by the bacteria
Borrelia burgdorferi and can be transmitted to humans trough the bites of
ticks. It is an important public health issue in US, where it is
the most common vector-borne disease. Other vertebrate hosts can
be infected and act as reservoirs. Host species differ
in their host competence, which is the ability to
sustain the population of ticks. There is also variation among
species in the reservoir competence, which is the
ability of an infected host to infect a tick.
The lizard Sceloporus occidentalis is by far the most competent host of
the tick Ixodes pacificus in the western US. Nevertheless, the
lizard has a very low reservoir competence, as it has highly effective
immune defenses against Borrelia burgdorferi. Therefore S. occidentalis can act as
an important barrier to the transmission of Lyme disease in the
region. Oddly enough, an experimental removal of lizards did not
increased tick infection prevalence, nor was there a marked increase in the tick
load on alternative hosts [1].
Questions
Can a mathematical model for Lyme disease transmission help to understand the experimental result described above? What else such a model can predict on:
- the infection risk to humans?
- host assemblages and Lyme disease prevalence in humans and reservoirs?
- management of reservoir populations to decrease the risk of infection?
Further well-grounded insights are welcome.
Hints
- There is a huge scientific literature on Lyme disease. Before start searching, define clearly the pieces of information you need. A 'What we know / what we need to know' brainstorm by the group is a good start.
- A key point is whether the experiment results reflect a stationary or a transient state.
Reference
- Andrea Swei, Richard S. Ostfeld, Robert S. Lane, and Cheryl J. Briggs. Impact of the experimental removal of lizards on lyme disease risk. Proceedings of the Royal Society B: Biological Sciences, 278(1720):2970–2978, 2011.