Pimped Rickettsiosis

What is Pimped Rickettsiosis ?

Pimped rickettsiosis (synonyms: gamazovy rickettsiosis, rickettsial smallpox) is a benign transmissible rickettsial infection. It is characterized by specific intoxication, moderately severe fever, the presence of primary affect and specific papular vesicular exanthema.

The disease was first described in 1946-1947. on the outskirts of New York and due to the similarity with chickenpox, it was called rickettsial pox (rickettsialpox). In the 50s. Twentieth century, the disease was detected in other areas of the United States, in Central and Southern Africa, in Uzbekistan, Turkmenistan and Kazakhstan.

Causes of Pimped Rickettsiosis

The causative agent of smallpox rickettsiosis is Rickettsia akariHuebneretal, 1946, belonging to the subgenus Dermacentroxenus. According to its properties, the pathogen is close to other rickettsiae from the group of tick-borne spotted fevers.

Small pox rickettsiosis is an endemic disease. The reservoir of infection in natural conditions are house rodents – mice and, possibly, rats. The circulation of rickettsiae is carried out through the Allogermanys sussanguineus gamasid mites, which parasitize on mice.

A person becomes infected with smallpox rickettsiosis in epizootic foci as a result of the attack and suction of infected gamasid mites.

Diseases in the form of sporadic cases are observed in urban and rural foci throughout the year with an increase in the incidence rate during the period of tick activity (May-August). More often men are ill.

Pimped rickettsiosis is known in North America, Central and Southern Africa, in the southern regions of Ukraine.

Pathogenesis during the Pimped Rickettsiosis

Having penetrated into the human body when a tick bites, rickettsiae multiply in reticuloendothelial cells, destroy them and enter the bloodstream, causing specific endotoxemia and morphological changes in the vessels of various organs. In the place of introduction of rickettsiae, an inflammatory reaction with lymphangitis and regional lymphadenitis develops – primary affect. Vascular lesions consist of perivascular lymphocyte infiltration, endothelium proliferation. Vascular disorders underlie the development of exanthema.

Symptoms of Pimply Rickettsiosis

The duration of the incubation period for smallpox rickettsiosis has not been precisely established and is apparently about 7-10 days.

Even in the incubation period (5–7 days before the development of intoxication syndrome), an inflammatory infiltration of 1-2 cm in size in the form of a red papule appears on the skin at the site of the tick bite. Then the papule turns into a vial that deeply penetrates the skin, and when wrinkled and dried, a black scab is formed. Primary affect is usually located on closed parts of the body, but can be noted on the back of the hands, neck, face, and is combined with regional lymphadenitis. Primary affect lasts 3–3 1/2 weeks; on healing it remains a tender scar.

After 5–7 days after the onset of primary affect, patients develop acutely intoxication syndrome, high fever (39–4 ° C), chills, sharp headaches, insomnia, muscle and back pain are noted. Remittent fever persists at high numbers for 6–7 days and ends with a critical or crisolytic decrease in temperature. From 2–3 days of the febrile period, a macular papular or erythematous rash appears.

After 1-2 days, the rash turns into a vesicular with an element diameter of 2-10 mm or more. The rash spreads throughout the body, including the face, and sometimes also the palmar and plantar surfaces. Elements of the rash are not abundant, easy to count. In rare cases, elements of the rash may not turn into vesicles or simulate erythema nodosa. In the future, the vesicles dry up, and in their place black crusts form, falling off on the 4-10th day of the disease without scarring.

Signs of damage to the cardiovascular system and internal organs are usually minor.

In the hemogram, it is possible to detect minor leukopenia, neutropenia with a shift of the leukocyte formula to the left, thrombocytopenia. ESR moderately increased.

The disease is uneventful and ends with recovery.

Diagnosis of Pimped Rickettsiosis

Clinical diagnosis is based on a complex of epidemiological and clinical data, of which the detection of primary affect with the subsequent development of fever and vesicular exanthema is most important.

Laboratory diagnosis is confirmed by isolating a rickettsia culture (on a chicken embryo, when guinea pigs are infected), and also by using serological methods (RAC with soluble R. akari antigen). In view of the antigenic affinity of R. akari with other members of the subgenus Dermacentroxenus, serological reactions are carried out in parallel with several antigens.

Differential diagnosis of smallpox rickettsiosis is carried out in relation to other tick-borne spotted fevers and chicken pox.

Treatment of Small Pox Rickettsiosis

Etiotropic agents, including tetracycline or chloramphenicol derivatives in usual dosages, are used throughout the febrile period and the first week of apyrexia. Carry out also measures for the prevention of secondary infection.

Prevention of Small Pox Rickettsiosis

Anti-epidemic measures in the outbreaks of smallpox rickettsiosis are aimed at reducing the number of mice by deratization and mites parasitizing them by disinsecting with the aid of acaricides, as well as at protecting people from gamasid mites attack with repellents. Specific prophylaxis of smallpox rickettsiosis has not been developed.