Prevalence of infection in a population can shape parasite virulenceJuly 18, 2005
If necessity is the mother of invention, the coevolutionary arms race is the mother of adaptation. For parasites and hosts engaged in an ongoing battle to gain advantage, those adaptations take many forms. In a new analysis in the premier open access journal PLoS Biology, Stephanie Bedhomme, Yannis Michalakis, and colleagues extend traditional methods of studying the coevolution of parasite virulence and host life history traits by introducing an additional variable: intraspecific competition between hosts. Unsurprisingly, the authors find that infected individuals pay a cost compared to their healthy counterparts. But surprisingly, both infected and uninfected individuals do better when their competitor is infected: parasite costs ¡Vand virulence ¡V therefore depend on the infection status of the competitors and for an infected mosquito, at least, you stand a better chance of getting your wings and leaving the natal lagoon if more of your larval neighbors are infected too.
To study the interplay between parasitism and intraspecific competition, Bedhomme et al. worked with the yellow fever mosquito Aedes aegypti and its natural enemy, the single-celled parasite Vavraia culicis. They divided recently hatched mosquito larvae into groups of 60 larvae, and exposed half of the groups to the parasite. Larvae were then placed two by two into vials. Vials contained either two uninfected larvae, two infected larvae, or one infected and one uninfected individual. Infected pairs took longer to develop than uninfected pairs, as expected. But with infected and uninfected pairs, infected larvae took longer to develop than their healthy partners, meaning they are more likely to succumb to the parasite. Competing against a healthy partner increased virulence by increasing development time. Interestingly, however, infected mosquitoes also fared better when paired with an infected competitor. These results suggest that a high incidence, or prevalence, of parasitic infection in the population means that healthy larvae face less competition and do better than they would if they had to compete with healthy individuals. Infected individuals will also do better if there's a high prevalence of infection because they are more likely to compete against equally poor competitors. Thus, by ignoring the effects of competition, standard models underestimate the full costs of virulence - and, more important, miss a significant link between a parasite's prevalence in a population and its virulence.
911 Avenue Agropolis
Montpellier, France 34394
PLEASE MENTION PLoS Biology (www.plosbiology.org) AS THE SOURCE FOR THESE ARTICLES. THANK YOU.
All works published in PLoS Biology are open access. Everything is immediately available without cost to anyone, anywhere--to read, download, redistribute, include in databases, and otherwise use--subject only to the condition that the original authorship is properly attributed. Copyright is retained by the authors. The Public Library of Science uses the Creative Commons Attribution License.
Related Infection Articles from Brightsurf:
New analysis by the University of Leeds and the University of Bern of more than 14,000 operations has found that using alcoholic chlorhexidine gluconate (CHG) halves the risk of infection in certain types of surgery when compared to the more commonly used povidone-iodine (PVI).
How plants shut the door on infection
A new study by an international team including University of Maryland scientists has discovered the key calcium channel responsible for closing plant pores as an immune response to pathogen exposure.
Sensing infection, suppressing regeneration
UIC researchers describe an enzyme that blocks the ability of blood vessel cells to self-heal.
Boost to lung immunity following infection
The strength of the immune system in response to respiratory infections is constantly changing, depending on the history of previous, unrelated infections, according to new research from the Crick.
Is infection after surgery associated with increased long-term risk of infection, death?
Whether experiencing an infection within the first 30 days after surgery is associated with an increased risk of another infection and death within one year was the focus of this observational study that included about 660,000 veterans who underwent major surgery.
Revealed: How E. coli knows how to cause the worst possible infection
The discovery could one day let doctors prevent the infection by allowing E. coli to pass harmlessly through the body.
UK study shows most patients with suspected urinary tract infection and treated with antibiotics actually lack evidence of this infection
New research presented at this week's European Congress of Clinical Microbiology & Infectious Diseases (ECCMID) in Amsterdam, Netherlands (April 13-16, 2019) shows that only one third of patients that enter the emergency department with suspected urinary tract infection (UTI) actually have evidence of this infection, yet almost all are treated with antibiotics, unnecessarily driving the emergence of antimicrobial resistance.
Bacteria in urine doesn't always indicate infection
Doctors should think carefully before testing patients for a urinary tract infection (UTI) to avoid over-diagnosis and unnecessary antibiotic treatment, according to updated asymptomatic bacteriuria (ASB) guidelines released by the Infectious Diseases Society of America (IDSA) and published in Clinical Infectious Diseases.
Subsidies for infection control to healthcare institutions help reduce infection levels
Researchers compared three types of infection control subsidies and found that under a limited budget, a dollar-for-dollar matching subsidy, in which policymakers match hospital spending for infection control measures, was the most effective at reducing the number of hospital-acquired infections.
Dengue virus infection may cause severe outcomes following Zika virus infection during pregnancy
This study is the first to report a possible mechanism for the enhancement of Zika virus progression during pregnancy in an animal model.
Read More: Infection News and Infection Current Events