Published Date: 2012-04-11 14:58:17
Subject: PRO/EDR> Rocky Mountain spotted fever - USA (02): (AZ)
Archive Number: 20120411.1097210
ROCKY MOUNTAIN SPOTTED FEVER - USA (02): (ARIZONA)
A ProMED-mail post
ProMED-mail is a program of the
International Society for Infectious Diseases
Date: Tue 10 Apr 2011
Source: The Payson Roundup [edited]
Gila County has reported an outbreak of potentially fatal spotted fever, with 8 cases already reported in southern Gila County.
So far, no cases have been reported in northern Gila County, according to Gila County Health and Emergency Services Director Michael O'Driscoll. In 2011, the bacteria spread by ticks caused 54 cases of the flu-like disease, which led to 11 deaths in 3 northern Arizona counties, including Gila County.
Arizona cases of the tickborne disease have risen steadily for the past decade, but spiked alarmingly in 2011. Officials say warming temperatures in April could cause a surge of cases through September, when ticks again become less active as temperatures drop.
Health officials urge residents to get tick collars for dogs and inspect both themselves and their pets after outdoor activities.
Rocky Mountain spotted fever is an infection that in Arizona is spread primarily by the common brown dog tick, mostly at higher elevations. The ticks often attach to dogs and can then move over to people.
The antibiotic doxycycline readily kills the bacteria if started within the 1st days symptoms emerge -- which includes fever, headaches, nerve pain, nausea, vomiting, diarrhea, and a rash -- often on the palms and soles of the feet. Doctors advise anyone in the at-risk area to start on the antibiotic immediately, rather than waiting for lab results to tell for sure whether they have spotted fever. The disease has a mortality rate of 3 to 5 percent, which topped 30 percent before the development of the antibiotics.
A tick has to remain attached to its host for about 24 hours before spreading the bacteria. Even in infected areas, fewer than 2 percent of ticks carry the bacteria.
Rocky Mountain spotted fever first appeared on the department's radar in 2002. Since then, the number of reported cases in the state has steadily increased, with 23 cases reported in 2009 and 52 cases in 2011. The disease caused 1 known death in 2009 and 5 deaths in 2011.
Some of the areas in Arizona most affected by the disease have been on American Indian reservations, with fewer resources to eradicate ticks and control free-roaming animals, said Jennifer McQuiston, the epidemiology activity lead for the Rickettsial Zoonoses Branch of the Centers for Disease Control and Prevention.
Most cases occur between spring and fall, but Arizona's mild winters allow ticks to survive year-round in many areas. "Arizona is unique in the sense that we have such a long outdoor season," Humble said. "It starts earlier and ends later."
Symptoms of Rocky Mountain spotted fever initially are similar to those of a severe case of the flu, which makes it difficult for doctors to differentiate it from other diseases, said McQuiston. Characteristic symptoms in the 1st few days include fever, severe headache, nausea, and muscle pain.
Keeping ticks away is the surest prevention. Officials suggest wearing light-colored clothing when hiking or camping to make spotting ticks easier, as well as wearing long-sleeved shirts and tucking pants into socks.
[Byline: Brittany Smith]
[As stated in the posting, it cannot be stressed enough that early recognition of this disease is quite important in minimizing morbidity and mortality. This is especially true in areas of the USA where the infection is not as classically known such as those outside the northwestern "Rocky Mountain" states as well as the Middle Atlantic states.
The incubation period of the disease is about a week after the tick exposure, long after the tick has detached. The presenting illness is generally nonspecific, fever, muscle pains, headache (the headache is usually described as quite severe). The rash begins in day 3 of illness, initially maculopapular at the wrists and ankles before becoming petechial and purpuric involving the palms and soles as well as spreading proximally to the truck. Purpura usually is not seen before the 6th day of illness. The mortality is indeed quite low if treatment (usually a tetracycline) is begun during the 1st 2 days of the rash or before.
Empiric treatment for this infection should always be begun in people with compatible symptoms inhabiting endemic areas during the spring and summer, even if no tick bite is known.
The female _Dermacentor variabilis_ (the American dog tick), a common vector for this infection, can be seen at http://bugguide.net/images/cache/3K9RLQWRIQTQU0L0P0K020H0P0Z020CQFKCRMQL0XQH0IQZ0U0R0W0Z0U0Q0IQTRIQOR7QYRP0JRXQS0G0OQX0VR.jpg.
The early rash of this disease can be seen at http://upload.wikimedia.org/wikipedia/commons/d/d2/Rocky_Mountain_spotted_fever_PHIL_1962_lores.jpg. - Mod.LL]
[The state of Arizona can be located on the HealthMap/ProMED-mail interactive map at http://healthmap.org/r/2aiH. Gila County can be seen on the map at http://www.digital-topo-maps.com/county-map/arizona.shtml. - Sr.Tech.Ed.MJ]