New research, however, suggests that cocoliztili was not a European disease, but rather a form of salmonella endemic to the region. In a paper paper published (paywall) Jan. 15 in Nature Ecology and Evolution Kristen Bos, an anthropologist at the Max Planck Institute in Munich, Germany, and her team identified the pathogen Salmonella enterica as a strong candidate for the pathogen that caused these deadly outbreaks. This particular strain of bacteria causes paratyphoid fever, which presents with the same symptoms consistent with accounts of cocoliztili.
S. Typhi and S. Paratyphi are transmitted through ingestion of fecally contaminated food or water. Variation in factors that influence these modes of transmission, such as host behavior or environmental factors, can result in fluctuating or complex seasonal dynamics.
This outbreak is an example of the combined effect of social behaviors, prevailing ecological conditions and improper disinfection of hospital wastewater on facilitating a sustained epidemic of paratyphoid fever. This study underscores the critical need for strict treatment measures of hospital wastewater and the maintenance of independent agricultural irrigation systems in rural areas.
Genome research suggests that enteric fever, a potentially lethal disease more commonly found in hot countries, was present in medieval Europe. Salmonella Paratyphi C causes enteric fever, a life-threatening infection, and has been detected in a 800 year old human skeleton discovered in Trondheim, Norway.
Typhoid and paratyphoid fever continue to be important causes of illness and death, particularly among children and adolescents in south-central and Southeast Asia, where enteric fever is associated with poor sanitation and unsafe food and water.
Now, DNA from 16th-century cocolitzli victims has offered up a somewhat unexpected new candidate: Salmonella enterica, or the bacteria that cause paratyphoid fever. The DNA evidence comes from the teeth of 11 people buried in a large Mixtec cemetery in southern Mexico. Prior archaeological work had linked the burials to the 1545 cocolitzli epidemic, and the city was likely abandoned after the disease killed so many of its inhabitants.
Because there is no definitive serologic test for typhoid or paratyphoid fever, the initial diagnosis often has to be made clinically. The combination of a history of risk for infection and a gradual onset of fever that increases in severity over several days should raise suspicion of typhoid or paratyphoid fever. Typhoid fever is a nationally notifiable disease.
Typhoid and paratyphoid fevers are systemic diseases caused by the bacteria Salmonella typhi and Salmonella paratyphi, respectively. Humans are the only reservoir for Salmonella typhi (which is the most serious), whereas Salmonella paratyphi also has animal reservoirs.