The disease and Panbio product training Rickettsia The disease and Panbio product training

Infectious Agent Rickettsia sp. Gram-negative coccoid or rod-shaped bacteria Obligate intracellular bacteria with an ability to grow in a variety of eukaryotic cells Do not survive well outside their host environment Different species cause different diseases

Infectious Agent cont... The Rickettsia are subdivided into three groups of species according to the type of clinical disease they cause: Typhus Group Spotted fever Group Scrub typhus Group They are further subdivided according to host and arthropod vector.

Infectious Agent cont... Spotted Fever Group Typhus Group R. australis R. rickettsii (Rocky Mountain spotter fever) R. conorii (Mediterranean spotted fever) R. sibirica Typhus Group R. prowazekii (Louse-borne typhus) R. typhi (Murine typhus) Scrub Typhus Group Orientia tsutsugamushi

Epidemiology Occurrence worldwide Mode of Transmission Epidemic and endemic regions Mode of Transmission Ticks, mites, and fleas

Distribution: Spotted fever group

Distribution: Typhus group

Distribution: Scrub typhus group

Clinical: Scrub Typhus Clinical manifestations: fever headache raised ulcer (eschar) rash (later in illness) myalgia lymphadenopathy Eschar

Clinical: Scrub Typhus Mortality rates 60% in untreated virulent strains 23% of all fever in endemic regions of Asia Antigenic diversity of strains exists within this group Vector - larval trombiculid mites (chiggers) Host - native rat species Incubation - 7 to 14 days Chigger infected foot

Clinical: Spotted Fever Vector - predominantly tick borne Host - rats, bandicoots Incubation - 5 to 7 days Common protein antigens with Typhus Benign course of infection common, mortality rate of 35% for RMSF Reactivation may occur

Clinical: Typhus Group R. prowazekii Vector - body louse Incubation - 8 to 12 days Brill-Zinsser typhus (reactivation)

Clinical: Typhus Group R. typhi (Murine/endemic typhus) R. typhi also known as R. mooseri Vector - oriental rat flea Self-inoculation, flea faeces & bites Non-specific clinical manifestations Low mortality rate

Life cycle of Rocky Mountain spotted fever, rickettsial pox and murine typhus. A. Life cycle of Rickettsia rickettsii in its tick and mammalian hosts. B. Rickettsia akari life cycle. C. Rickettsia typhi life cycle. Azad A.F. & C.B. Beard (1998) Rickettsial Pathogens and Their Arthropod Vectors. Emerg. Infect. Dis.4:179-186

Area where murine typhus is a risk Areas in which murine typhus poses a risk according to seroepidemiologic studies, case series, or imported cases in traveller. Parola, P. (1998) Murine typhus in travelers returning from Indonesia. Emerg. Infect. Dis. 4:677-680.

Clinical notes Prevention Treatment Use of mite repellents to exposed skin surfaces Elimination of mites from populated areas Doxycycline has been found to be an effective preventative measure in a small Malaysian trial An effective vaccine is yet to be developed Treatment Doxycycline

Antibody response Antibody levels may be low or absent during early infection. Antibody response may be delayed or eliminated in some patients being treated with antibiotics. Elevated or rising IgM and/or IgG antibodies indicate recent or active infection. Infection results in prolonged immunity to homologous strain. During a period of months after primary infection, infection with heterologous strain will result in mild disease.

Diagnosis Weil Felix Dot blot EIA (Dip-S-Ticks from Panbio) OX-19 (Typhus) OX-K strain Proteus mirabilis (Scrub Typhus) Dot blot EIA (Dip-S-Ticks from Panbio) IFA (Gold Standard) Agglutination based assays indirect haemagglutination (IHA) latex agglutination (LA) ELISA

Weil Felix Non-specific test that uses various Proteus spp. Test based on presence of common antigens in both the Rickettsia and Proteus spp. Lacks both sensitivity and specificity & should no longer be used as better methods available Leptospirosis and some other febrile illnesses may cause a positive Weil-Felix reaction Re-infection does not always lead to a rise in Weil-Felix agglutinins

Agglutination-based assays Indirect haemagglutination (IHA) & latex agglutination (LA) Detect antibodies to Spotted fever and Typhus group. Uses solubilised antigen from purified rickettsiae absorbed onto untreated red blood cells. Detects IgG and IgM

Panbio Dip-S-TickTM Panbio Dipsticks (Dot EIA) for: Principle:- R. typhi (Murine typhus) Total IgG R. rickettsii (RMSF) Total IgG R. conorii Total IgG Principle:- specific antibodies if present in patient’s serum bind to the antigen spotted on membrane reaction visualised by addition of alkaline phosphatase-conjugated anti-human antibodies which is then reacts with enzyme substrate reagent to form a spot.

Panbio IFA Excellent sensitivity & specificity Panbio has IFA slides for the following:- Typhus group Murine Typhus (R. typhi) Louse-borne typhus (R. prowazekii) Scrub Typhus Group Scrub Typhus (O. tsutsugamushi) Spotted Fever Group Rocky Mountain Spotted Fever (R. rickettsii) Mediterranean Spotted Fever (R. conorii)

Panbio IFA

Panbio Rickettsial ELISA kits Scrub Typhus Group IgG Cat # E-RST01G Scrub Typhus Group IgM Cat # E-RST01M Fast - 1.5 hours total assay time Spotted Fever Group IgG Cat # E-RSF01G Spotted Fever Group IgM Cat # E-RSF01M

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