Murine typhus is one of several diseases once assumed to have been all but eradicated in the continental U.S. thanks to better pubic health programs since the mid-20th Century, but that have been staging a comeback in Texas recently. Or perhaps these onetime plagues never really were entirely eliminated, but no one was looking for them or trained to recognize them, since they were rarely if ever covered by medical schools.
According to Dr. Peter Hotez in his book “Forgotten People, Forgotten Diseases”, the second edition of which was released in May, “We have uncovered an extraordinary disease burden from NTDs in Texas and adjacent Gulf Coast states, including Chagas disease, congenital cytomegalovirus, dengue, murine typhus, toxocariasis, trichomoniasis and West Nile virus.” “I think these diseases have been around for a while,” Dr. Hotez commented to Al Jazeera America’s Amy Maxman last week, “But no one has been looking.”
Dr. Hotez is dean of the National School of Tropical Medicine at Baylor College of Medicine, where he is a professor in the Department of Pediatrics and the Department of Molecular Virology and Microbiology, head of the Section of Pediatric Tropical Medicine and the Texas Children’s Hospital Endowed Chair of Tropical Pediatrics, president of the Sabin Vaccine Institute and Texas Children’s Hospital Center for Vaccine Awareness and Research, and the fellow in disease and poverty at Rice University’s Baker Institute for Public Policy.
Ms. Maxman observes that murine typhus, which is typically contracted by humans via fleas carried by rats that for example once thrived in the port city of Galveston, near Houston. However, after the government introduced rat trapping programs and dusted large swaths of land with DDT during the 1940s and ’50s, no major outbreaks like one in 1944 that infected more than 5,400 people murine typhus, have been recorded in the U.S.
However, thanks to the efforts of Dr. Hotez and other neglected tropical disease (NTG) researchers, specialists and advocates, Houston’s National School of Tropical Medicine is now teaching doctors how to recognize neglected diseases that are skipped over in medical school. Baylor College of Medicine and Texas Children’s Hospital stepped up to make Dr. Hotez’ vision for such a facility a reality with a 10-year, $20 million start-up package, with the objective of having it become a national (and international) resource for doctors, scientists and patients across the U.S. The school also incorporates research laboratories tasked with developing vaccines for neglected diseases that could save lives on a global scale.
The Texas capital City of Austin notes on the Austin/Travis County Health and Human Services Department Website that Typhus has been reported in the Austin/Travis County area for the past several years and is now endemic to the Austin area. As of September 11, 2013, 13 cases of typhus had been reported in Travis County in 2013, most frequently reported from May through September. continues to investigate and monitor all reported cases of typhus. However, the Texas Department of State Health Services (DSHS) Infectious Disease Control Unit reports that most murine typhus cases identified in Texas occur in South Texas from Nueces County southward to the Rio Grande Valley, with a few cases reported in other parts of the state each year. The DSHS says the apparent increase in the number of typhus cases reported in Texas can be attributed to active surveillance for typhus being conducted in the border counties between 2006 and 2009; and beginning in 2008, typhus expanding into new areas. Also, increased awareness of murine typhus in the medical community in these new areas contributed to a record number of cases being reported in 2011.
The typhus group of illnesses are caused by rickettsiae, gram-negative obligate intracellular bacteria transmitted by bites of infected arthropod insects or exposure to their feces.
The DSHS describes murine typhus, also called fleaborne or endemic typhus, as a rickettsial disease caused by the bacterium Rickettsia typhi, with another organism, R. felis, possibly playing a role in causing infections. Rats and their fleas are the natural reservoirs (animals that both maintain and transmit the disease organism) and primary vectors in the spread of murine typhus, while other animals, such as opossums and domestic cats, may also be involved in transmission of the disease to humans. Fleas, such as the rat flea, Xenopsylla cheopis, and the cat flea, Ctenocephalides felis, are the most common vectors of murine typhus. Most fleas defecate while biting, and the feces of infected fleas contain the rickettsiae organism, which he enter the body through the bite wound or from a person scratching a bite area. It is also possible to become infected with murine typhus by inhaling contaminated, dried flea feces, but that method of transmission less common as transmission from a biting flea. There is a related, and more severe disease called epidemic typhus that is transmitted by Rickettsia prowazekii spread by lice.
The incubation period for murine typhus is 8 to 16 days. Symptoms of the disease include abdominal pain, backache, headache, extremely high fever (105 – 106 degrees Fahrenheit) that may last up to 2 weeks, hacking, dry cough, joint and muscle pain. nausea, and vomiting. Five or six days after the initial symptoms, a rash that starts on the trunk of the victim’s body and spreads to the arms and legs.
The incubation period for epidemic louse-borne typhus is seven days. Symptoms of epidemic typhus include chills, confusion, cough, delirium, high fever (104 degrees Fahrenheit), joint pain (arthralgia), lights that appear very bright; light may hurt the eyes, low blood pressure, rash that begins on the chest and spreads to the rest of the body (except the palms of the hands and soles of the feet), severe headache, severe muscle pain (myalgia), stupor and a rash initially a light rose color that fades when you press on it, but later becomes dull and red and does not fade. People with severe typhus may also develop small areas of bleeding into the skin (petechiae). Patients with epidemic typhus may need intravenous fluids and oxygen.
Without treatment, death may occur in 10 – 60 percent of patients with epidemic typhus, with patients over age 60 having the highest risk of death. Patients who receive treatment quickly should completely recover, untreated cases may become hemorrhagic and necrotic. Less than two percent of untreated patients with murine typhus may die. Possible complications include renal insufficiency, pneumonia, and central nervous system damage.
Prompt antibiotic treatment will cure nearly all patients, but if left untreated a case of typhus may linger for several months, so the DSHS advises that anyone who suspects they may have murine typhus, they should see a doctor as soon as possible. Waiting too long to see a doctor may result in hospitalization. Murine typhus is easily treated with certain antibiotics, and an infection recovered from confers lifetime immunity. However, Brill-Zinsser disease, a mild delayed relapse form of epidemic typhus, occurs when the Rickettsia prowazekii bacteria re-activate in an individual who was previously infected, and is is more common in the elderly. This reactivation event can then be transmitted to other individuals through fecal matter of the louse vector, and form the vector focus for a new epidemic of typhus.
However, prevention and avoidance are better than treatment, and the DSHS advises that the best way to protect yourself and your family from murine typhus is to:
• Clean your yard so that rodents, opossums, and stray cats cannot live there.
Remove any brush or trash, keep the grass mowed, and keep firewood off the ground.
• Don’t leave pet food out at night as this attracts other animals.
• Prevent rodents from living in your house.
• Treat for fleas before you begin rodent control in your house or yard. Otherwise, when the rodents die, the fleas will search for new hosts, possibly you and your family. There are several commercial flea control products on the market. Pick one and follow the label instructions.
• If you own pets, control the fleas on them regularly. If they come in contact with infected fleas, they could bring them home to you. Ask a veterinarian about flea control products that are safe to use on your pets.
Measures to get rid of lice when an infection has been found include bathing, boiling clothes or avoiding infested clothing for at least five days (lice will die without feeding on blood), and using insecticides.
Questions related to murine typhus or flea control can be addressed to a physician or a veterinarian, your local health department, or the Texas Department of State Health Services – Zoonosis Control Branch.
Texas Department of State Health Services (DSHS) Infectious Disease Control Unit: http://www.dshs.state.tx.us/idcu/disease/murine_typhus/
Baylor Scott & White Health:
Rice University Baker Institute:
City of Austin Department of Health: