Rabbits: perhaps bad after all
You may recall that there is some controversy as to the extent and nature of the Rabbit Menace. Here is another data point for you to consider, before you head off to PetSmart to get your new companion. Via the journal Global Change Biology, a tale to terrify you.
Many herbivores carry a variety of intestinal helminth parasites, which are acquired during feeding and passed on in the feces. Two soil dwelling helminth parasites of the European rabbit (Oryctolagus cuniculus) have been used to model the interactions between hosts and pathogens in controlled laboratory systems. The nematodes Graphidium strigosum and Trichostrongylus retortaeformis have been extensively studied in the rabbit for decades. Neither nematode typically causes a lethal infection in rabbits, but does lead to weight loss and decrease in fecundity in infected animals. A quick search through Pubmed did not turn up any obvious infections of humans, but presumably the elderly, the very young, and otherwise immunocompromised are at some measure of risk of infection.
The current study focuses on the ambient temperature, egg hatching rates of the nematode in soil, and survival of the larvae, and came about due to observations of generally increasing air temperature measurements at the study site over a 30 year period. These observations have led the authors to question whether host/parasite dynamics might additionally be affected by environmental conditions. What they found was that T. retortaeformis, but not G. strigosum, showed higher rates of egg hatching and larval survival with increases in temperature. This result contrasted the 30 year period of field studies, which indicated that G. strigosum infection rates increased during the interval of generally increasing ambient temperature trends.
Overall, the study underscores the dynamic nature of the host/parasite interaction, and the potential that shifting environmental conditions enable certain microorganisms to have competitive advantages over others. Although both of these worm pathogens pose no known risk to humans, many other bacterial, fungal, protozoan, and metazoan pathogens of humans may demonstrate similar responses to altered environmental conditions seen, as mean global temperatures continue to increase.