Fleas are ectoparasitic blood-sucking insects with the ability to jump, which commonly infest wild and domestic animals (mainly dogs and cats) but also humans.
West Nile virus is a mosquito-borne flavivirus that is maintained in an enzootic cycle between mosquitoes and birds. Humans and horses are incidental dead-end hosts.
Meningococcal disease is caused by Neisseria meningitidis, a bacterium with human carriers as the only reservoir. It is carried in the nose, where it can remain for long periods without producing symptoms.
Despite good access to effective antibiotics, Streptococcus pneumoniae (pneumococci) is still a major cause of disease and death in both developing and developed countries. Pneumococci are the main cause of bacterial respiratory tract infections, such as pneumonia, middle ear infection, and sinusitis, in all age groups.
The transmission of Clostridioides difficile can be patient-to-patient, via contaminated hands of healthcare workers or by environmental contamination.
West Nile virus (WNV) infection is a mosquito-borne zoonosis. The virus is transmitted among birds via the bite of infected mosquitoes and incidentally humans and other mammals may become infected.
Plague is caused by the bacillus Yersinia (Y.) pestis, belonging to the family of the Enterobacteriaceae. It evolved several thousand years ago from Y. pseudotuberculosis.
Plague is caused by Yersinia pestis bacteria. Blood sucking fleas transmit the bacteria among animals, and various species of rodents can become infected.