Rocky Mountain Spotted Fever is a potentially fatal tick-borne disease that occurs primarily in North America - the US and Canada. Rocky Mountain spotted fever is caused by the bacterium Rickettsia rickettsii, which is transmitted by ticks. What are the symptoms of Rocky Mountain Spotted Fever? What is the treatment?

Rocky Mountain Spotted Feveris an acute, contagious tick-borne disease caused by bacteria - rickettsiaRickettsia rickettsii .

Rocky Mountain spotted fever belongs to the group of rickettsial. Rickettsiae are a group of acute fever diseases caused by rickettsiae - various species of bacteria belonging to the order Rickettsiales. Their clinical course may be similar, nevertheless the epidemiological and etiological features are quite different.

  • group of rash typhus - epidemic, sporadic and rash typhus
  • Spotted fever group: Rocky Mountain spotted fever, Mediterranean fever, North Asian tick fever, Rickettsial pox, Queensland tick fever, hard fever
  • infections caused by microorganisms of the genus Coxiella, Bartonella, Anaplasma

Rocky Mountain Spotted Fever has been reported in the United States since the 1920s.

Rocky Mountain Spotted Fever - routes of infection

Rickettsia rickettsii is transmitted by several species of ticks - mainly Dermacentor tick species ( Dermacentor variabilis ,Dermacentor andersoni ). They are the most important vectors of this pathogen in North America.

The US states with the highest number of cases per million inhabitants are North Carolina, Oklahoma, Arkansas, Tennessee, and Missouri. There are 60 percent of them. cases of illness.

On the other hand, in the southwestern United States (as well as parts of Mexico), the disease is transmitted mainly through the dog tick ( Rhipicephalus sanguineus ).

Infected tick bites and disease development can occur throughout the year, but the season is in spring and summer, peaking in June and July. However, this seasonality varies somewhat across regions of the country due to climate and strain vectors. In Arizona, where the broadcast isrelated to the canine tick, the peak incidence starts in April and lasts until October.

People who have frequent contact with dogs, who live near wooded areas or areas with long grass, are at increased risk.

Rocky Mountain Spotted Fever - Symptoms

Symptoms of Rocky Mountain spotted fever appear within 2-14 days of a tick bite:

  • fever
  • non-itchy rash (small, flat pink patches) occurs in 90 percent of sick and has a characteristic appearance on the skin of forearms, wrists and ankles 2-5 days after the onset of fever. In some of this group, rash is not present at the beginning of the disease. It develops in the late stage of the disease, after the initiation of treatment. In 10 percent sick rash is not present
  • headache
  • stomach pains (may mimic appendicitis or other causes of acute abdominal pain)
  • lack of appetite
  • muscle aches
  • nausea, vomiting

Rocky Mountain Spotted Fever Rash

Source: youtube.com/Carlsson

Important

Rocky Mountain Fever - complications

In cases of untreated disease (or treated improperly), the mortality rate can be as high as 6%, and the cause of death may be developing respiratory failure, liver failure, kidney failure and heart failure.

Rocky Mountain Spotted Fever - diagnosis

Conversation with the patient plays a huge role due to the geographical conditions of the occurrence of individual disease entities, as well as vectors that transmit rickettsiae. In addition, laboratory tests should be performed:

  • usually immunofluorescence test (remember that antibodies appear 7-10 days after the onset of general disease symptoms)
  • PCR - positive result before the appearance of antibodies, the type of material depends on the type of disease (suspected), e.g. blood, skin biopsy or scab (e.g. African tick fever)
  • cell culture (specific media
  • PCR test based on cell cultures of skin swabs

Rocky Mountain Spotted Fever - treatment

Treatment of rocky mountain spotted fever consists in administering antibiotics - doxycycline 100mg twice / day for 5-10 days. Treatment is most effective if started within 5 days of onset of symptoms.

Source:

Rocky Mountain Spotted Fever (RMSF), https://www.cdc.gov/rmsf/symptoms/index.html

Category:

Parasitic diseases