Fleas test positive for plague near Flagstaff, — No Need to Freak Out, Health Officials Say
FLAGSTAFF, AZ - Fleas collected from a remote area of Coconino County have tested positive for plague.
Coconino County health officials said Tuesday the fleas were collected from burrows that were being monitored due to a die off of prairie dogs around Doney Park, northeast of Flagstaff.
Area residents have been notified and the burrows have been treated.
Plague is a disease carried by rodents and rabbits, and sometimes of the predators that feed on them. The disease can be transmitted to humans and other animals by the bite of an infected flea, or by direct contact with an infected animal.
Symptoms include fever, chills, headache, weakness, muscle pain, and swollen lymph glands.
Thank you Stacie
Plague, caused by a bacterium called Yersinia pestis, is transmitted from rodent to rodent by infected fleas.
Plague is characterized by periodic disease outbreaks in rodent populations, some of which have a high death rate. During these outbreaks, hungry infected fleas that have lost their normal hosts seek other sources of blood, thus increasing the increased risk to humans and other animals frequenting the area.
Epidemics of plague in humans usually involve house rats and their fleas. Rat-borne epidemics continue to occur in some developing countries, particularly in rural areas. The last rat-borne epidemic in the United States occurred in Los Angeles in 1924-25. Since then, all human plague cases in the U.S. have been sporadic cases acquired from wild rodents or their fleas or from direct contact with plague-infected animals.
Rock squirrels and their fleas are the most frequent sources of human infection in the southwestern states. For the Pacific states, the California ground squirrel and its fleas are the most common source. Many other rodent species, for instance, prairie dogs, wood rats, chipmunks, and other ground squirrels and their fleas, suffer plague outbreaks and some of these occasionally serve as sources of human infection. Deer mice and voles are thought to maintain the disease in animal populations but are less important as sources of human infection. Other less frequent sources of infection include wild rabbits, and wild carnivores that pick up their infections from wild rodent outbreaks. Domestic cats (and sometimes dogs) are readily infected by fleas or from eating infected wild rodents.
Plague is a highly virulent disease believed to have killed millions during three historic human pandemics. Worldwide, it remains a threat to humans and is a potential agent of bioterrorism. Dissemination of Yersinia pestis, the etiological agent of plague, by blocked fleas has been the accepted paradigm for flea-borne transmission. However, this mechanism, which requires a lengthy extrinsic incubation period before a short infectious window often followed by death of the flea, cannot sufficiently explain the rapid rate of spread that typifies plague epidemics and epizootics. Inconsistencies between the expected rate of spread by blocked rat fleas and that observed during the Black Death has even caused speculation that plague was not the cause of this medieval pandemic. We used the primary vector to humans in North America, Oropsylla montana, which rarely becomes blocked, as a model for studying alternative flea-borne transmission mechanisms. Our data revealed that, in contrast to the classical blocked flea model, O. montana is immediately infectious, transmits efficiently for at least 4 d postinfection (early phase) and may remain infectious for a long time because the fleas do not suffer block-induced mortality. These factors match the criteria required to drive plague epizootics as defined by recently published mathematical models. The scenario of efficient early-phase transmission by unblocked fleas described in our study calls for a paradigm shift in concepts of how Y. pestis is transmitted during rapidly spreading epizootics and epidemics, including, perhaps, the Black Death.
People can get the plague when they are bitten by a flea that carries the plague bacteria from an infected rodent. In rare cases, you may get the disease when handling an infected animal.
Certain forms of the plague can be spread from human to human. When someone with pneumonic plague coughs, microscopic droplets carrying the infection move through the air. Anyone who breathes in these particles may catch the disease. An epidemic may be started this way. In the Middle Ages, massive plague epidemics killed millions of people.
Today, plague is rare in the United States, but has been known to occur in parts of California, Utah, Arizona, Nevada, and New Mexico.
There three most common forms of plague are:
- Bubonic plague — an infection of the lymph nodes
- Pneumonic plague — an infection of the lungs
- Septicemic plague — an infection of the blood
The time between being infected and developing symptoms is typically 2 to 10 days, but may be as short as a few hours for pneumonic plague.
Risk factors for plague include a recent flea bite and exposure to rodents, especially rabbits, squirrels, or prairie dogs, or scratches or bites from infected domestic cats.more
May 18, 2011