What is the Weil-Felix test and purpose?

The Weil-Felix test is a nonspecific agglutination test that utilizes antigenic cross-reactivity between rickettsiae and certain non-motile Proteus serotypes for detection of anti-rickettsial antibodies (so-called Weil-Felix antibodies) in a patient’s serum.

What is rickettsial infection?

Rickettsial infections and related infections (such as anaplasmosis, ehrlichiosis, and Q fever) are caused by an unusual type of bacteria that can live only inside the cells of another organism. Most of these infections are spread through ticks, mites, fleas, or lice.

What is rickettsial test?

Rickettsial testing is used to determine whether a person with symptoms and a recent history of potential exposure to a specific rickettsia has been infected.

What does the word rickettsial mean?

: any of a various gram-negative, parasitic bacteria (order Rickettsiales and especially genus Rickettsia) that are transmitted by biting arthropods (such as lice or ticks) and cause a number of serious diseases (such as Rocky Mountain spotted fever and typhus)

What is Brill Zinsser disease?

Brill-Zinsser disease is a recurrent form of epidemic typhus that is unrelated to louse infestation and develops sporadically years after the primary illness. Clinical features are similar to, but milder than, those of epidemic typhus (1).

What if Weil Felix test is positive?

A positive tube would show visible flocculation or granulation, which is accentuated when the tube is gently agitated. The titer corresponds to the most dilute tube in the series that still shows positivity. Generally, a titer of ≥1:320 is considered diagnostic.

What symptoms are associated with most rickettsial infections?

Most tick-borne rickettsial diseases cause sudden fever, chills, and headache (possibly severe). These symptoms commonly are associated with malaise and myalgia. Nausea, vomiting, and anorexia are common in early illness, especially with RMSF and HME.

What is a positive widal test?

The Widal test is positive if TO antigen titer is more than 1:160 in an active infection, or if TH antigen titer is more than 1:160 in past infection or in immunized persons. A single Widal test is of little clinical relevance especially in endemic areas such as Indian subcontinent, Africa and South-east Asia.

What antigens strains are used for Weil Felix test?

Proteus OX2, Proteus OX19, Proteus OXK antigen suspensions are employed for the Weil-Felix test. The Weil-Felix test is based on the principle that some non-motile strains of Proteus share common somatic antigens with certain species of Rickettsia.

What if Weil-Felix test is positive?

How do you cure Weil-Felix?

Weil-Felix test is considered sufficient for diagnosis in most cases but PCR is confirmatory (1,2). Most cases are treated with doxycycline (100 mg PO bid for 5 days) or cholramphenicol (500 mg qid PO for 7-10 days) or ciprofloxacin (750 mg bid PO for 5 days). Mortality from untreated typhus fever is up to 15\% (3).