Infections are typically seen in populations living in unsanitary, crowded conditions; outbreaks are often associated with wars, famines, floods and other disasters. Most epidemics occur during the colder months.
Sporadic cases of zoonotic typhus are seen in the United States. Deaths have not been seen in the zoonotic form, regardless of treatment. Infections can be transmitted to humans from this species but little has been published about the disease in squirrels.
Dogs have been experimentally infected but seroconverted with no clinical signs; no organisms were recovered from the blood.
Azad A. Breitschwerdt E. Hegarty, M. Davidson and N. Edited by M. Beers and R. Huffman J. Walker, D. Edited by Samuel Baron. New York; Churchill Livingstone, Governor Sheila Oliver. Related Links. About NJDA. Top of Page. Other Ricketssial Zoonosis Diseases. Links with this icon indicate that you are leaving the CDC website. Linking to a non-federal website does not constitute an endorsement by CDC or any of its employees of the sponsors or the information and products presented on the website.
You will be subject to the destination website's privacy policy when you follow the link. CDC is not responsible for Section compliance accessibility on other federal or private website. The latter form is sporadic and not transmissible. Immunofluorescence is the routine diagnostic method. Serum from the convalescent phase is required to confirm the initial diagnosis. Molecular detection and identification is used also.
This technique is rapid, sensitive, specific, and can be applied to a wide spectrum of samples with different origins e. Cell culture can be used to isolate Rickettsia spp. Relevant laboratory abnormalities include anemia, thrombocytopenia, increased erythrocyte sedimentation rate, increased hepatic transaminase activity, and hypoalbuminemia.
The differentiation of epidemic typhus from endemic typhus by serology can only be distinguished by western blot assays combined with cross-adsorption tests. Distinction between primary infection and the recrudescent form of epidemic typhus, termed Brill—Zinsser disease, is based on the immunoglobulin M measure in primary infection.
Doxycycline administration should be started in any suspected case without waiting for laboratory confirmation. Duration of treatment is linked to the clinical manifestations and should continue at least 3 days after the patient becomes afebrile.
Ciprofloxacin did not protect a patient with epidemic typhus from death. It may be used as an alternative treatment for endemic typhus. However, a poor response to this antibiotic was reported in one case.
Possible complications include: seconday bacterial infection, myocarditis, peripheral gangrene, or venous thromboembolism. Typhus group rickettsiae are transmitted by insects lice for R. This association might not be completely specific; other arthropods may be implicated in the epidemiology of these rickettsiae. Endemic typhus occurs more regularly in warm climates, which may be explained by the faster growth rate of R.
Furthermore, fleas propagate efficiently in hot, dry environments. The typhus group of rickettsiae includes R. After infection, typhus group rickettsiae spread directly to the blood stream where they target endothelial cells.
Bacteria bind to the membrane of the target cell and phagocytosis is induced. Typhus group rickettsiae multiply within the cytosol until mechanical lysis. The infection of additional cells occurs, inducing generalized vasculitis and vascular dysfunction.
Inflammatory mediators cytokines, prostaglandins, and products of coagulation are released and the phenotype of infected cells and the tightness of interendothelial cell junctions are modified, leading to an increase in microvascular permeability.
Passage of plasma, plasma proteins, and immune cells into surrounding tissues and lesions occurs, leading to rash, edema, and hemorrhage. Immune cells release proteases and oxygen radicals that can contribute to the severity of tissue damage. In the case of epidemic typhus, after clinical cure bacteria are not totally cleared. Emerging infectious disease agents and their potential threat to transfusion safety. Epidemic louse-borne typhus.
Facts about epidemic louse-borne typhus. Facts about epidemic louse-borne typhus Factsheet. Twitter Facebook Linked In Mail. Introduction Louse-borne typhus epidemic typhus or exanthematic typhus is a vector-borne disease caused by Rickettsia prowazekii and transmitted through infected faeces of the body louse Pediculus humanus humanus. The pathogen Louse-borne typhus is caused by Rickettsia prowazekii , an obligate intracellular gram-negative bacterium with a singular circular chromosome of 1.
Rickettsia typhi , responsible for endemic typhus, also belongs to the typhus group of the Rickettsia genus but is transmitted by fleas. Genomic analysis demonstrates two strains of Rickettsia prowazekii ; one isolated only from humans and another identified in flying squirrels Glaucomys volans which is responsible only for sporadic typhus cases. Clinical features and sequelae [1,2] The incubation period of epidemic louse-borne typhus is typically between 10 and 14 days.
The symptoms are associated with infections of endothelial cells and the subsequent rickettsia-induced vasculitis. The onset of symptoms is usually sudden after a prodromal phase of malaise lasting a few days. Rash is frequent and this clinical feature is noteworthy for supporting the diagnosis.
It starts in the axillae, mostly spreads over the trunk, and may extend centrifugally towards extremities generally sparing the face, palms and soles. Lesions initially appear as non-confluent erythematous and blanching areas, but later as petechial and even purpuric lesions, and are often attributed to vasculitis in around one third of patients.
Various central neurological system symptoms can be observed e. Splenomegaly may also be seen. Complications of systemic vasculitis can occur with multiple organ dysfunction syndrome, and peripheral and cerebral thrombosis.
Common laboratory abnormalities include thrombocytopenia, increased blood urea and increased hepatic transaminase levels. Brill—Zinsser disease is a late relapse which can occur months or years after the initial R.
The clinical presentation is similar to louse-borne typhus but is associated with a lower mortality rate. Sporadic cases of R. Differential diagnosis includes malaria, typhoid fever, viral haemorrhagic fever, leptospirosis, endemic typhus, tick-borne and louse-borne relapsing fevers, non-typhoidal salmonellosis, meningococcal septicaemia and meningitis. Epidemiology [1] Historically, large suspected outbreaks of epidemic typhus occurred worldwide especially among military troops during the Napoleonic Wars, and first and second World Wars.
Epidemic typhus was widespread globally prior to the introduction of modern antibiotics. Outbreaks of louse-borne typhus occur during the colder months and have been associated with the overcrowded and unsanitary conditions that are prevalent in time of war. Epidemic typhus is rarely found among travellers. It can occur in vulnerable populations where body lice are prevalent e.
Between the s and s, large epidemics of louse-borne typhus became less frequent and its geographical distribution has declined due to improvements in living standards.
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