TYPHUS Causative Agents TYPHUS Rickettsia typhi (murine typhus) and Orientia tsutsugamushi (scrub typhus). Causative Agents IncubationRickettsia typhi Period (murine typhus) and Orientia tsutsugamushi (scrub typhus). 1 to 3 weeks Incubation Period Infectious1 to 3 weeks Period Zoonoses with no human-to-human transmission. Infectious Period TransmissionZoonoses with no human-to-human transmission. Scrub typhus: Bite of grass mites (larval trombiculid mites) MurineTransmission typhus: Bite of rat fleas (also cat and mice fleas) RodentsScrub typhus: are the Bite preferred of grass and mites normal (larval hosts. trombiculid mites) Murine typhus: Bite of rat fleas (also cat and mice fleas) EpidemiologyRodents are the preferred and normal hosts. Distributed throughout the Asia-Pacific rim and is a common cause of pyrexia of unknownEpidemiology origin throughout SE Asia. Occupational contact with rats (e.g. construDistributedction throughout workers inthe makeAsia-Pshiftacific container rim and isfacilities, a common shop cause owners, of pyrexia granary of workers,unknown andorigin garbage throughout collectors) SE orAsia. exposure Occupational to mite habitat contacts in lonwithg grassrats (e.g. hikersconstru andction so ldiers)workers are inrisk make factors.-shift container facilities, shop owners, granary workers, and garbage collectors) or exposure to mite habitats in long grass (e.g. Inhikers Singapore, and soldiers) a total are ofrisk 13 factors. laboratory confirmed cases of murine typhus were r eported in 2008. The majority of cases were foreign workers. In Singapore, a total of 13 laboratory confirmed cases of murine typhus were Clinicalreported Featuresin 2008. The majority of cases were foreign workers. Fever Clinical Headache Features (prominent) MyalgiaFever ConjunctiHeadache val(prominent) suffusion MaculopapularMyalgia rash Conjunctival suffusion Scrub Maculopapular typhus may alsorash have: relative bradycardia, eschar (80%), painful regional adenopathy, hepatosplenomegaly, meningoencephalitis and renal failure. Scrub typhus may also have: relative bradycardia, eschar (80%), painful regional Murineadenopathy, typhus hepatosplenomegaly, is generally a mild meningoencephalitisinfection. Untreated andscrub renal typhus failure. has appreciable mortality. Murine typhus is generally a mild infection. Untreated scrub typhus has appreciable Investigationsmortality. White cell count is usually normal (may be leucopoenic). Investigations Thrombocytopenia is common. LiverWhite function cell count tests is usuallymay show normal mild (may elevation be leucopoenic). of transaminases. Thrombocytopenia is common. Liver function tests may show mild elevation of transaminases. 131 131 Mild hyponatraemia. Rickettsial-specific serological diagnosis is available. Ideally, blood is collected asMild early hyponatraemia. in the course of disease as possible and a second sample collected after Rickettsial1-2 weeks -(diagnosticspecific serological titres are diagnosispresent in is approximately available. Ideally, 50% bloodof murine is collected typhus aspatients early inwithin the course 1st week of anddisease almost as possible all patients and within a second 15 sampledays of collectedonset of after 1il-l2ness). weeks (diagnostic titres are present in approximately 50% of murine typhus Thepatients Weil within-Felix 1 testst week depends and almost on similarity all patients between within antigens 15 days ofof onsetRickettsia of and Proteusillness). spp. and is not recommended as Rickettsia-specific tests are now avaiThe lable.Weil -TheFelix OX19 test depends (at a cut on-off similarity of 1/160) betweenis fairly antigensspecific forof murineRickettsia typhus and butProteus not asspp. sensitive and is as not EIA. recommended The OXK (scrubas Rickettsia typhus)-specific in local testsexperience are now is avaiparticlable.ularly The prone OX19 to cross (at a- reactionscut-off of with 1/160) other is diseasesfairly specific like dengue. for murine typhus but not as sensitive as EIA. The OXK (scrub typhus) in local experience is Notificationparticularly prone to cross-reactions with other diseases like dengue. Not a notifiable disease. Inform Ministry of Health (Form MD131 or electronically Notificationvia CD-LENS) if outbreak suspected. Not a notifiable disease. Inform Ministry of Health (Form MD131 or electronically Managementvia CD-LENS) if outbreak suspected. Doxycycline 100 mg bd x 5-10 days or for > 3 days after defervescence occurs Management(fever should usually resolve within 72 hours of treatment initiation). (Alternative)Doxycycline 100Ciprofloxacin mg bd x 5 -10500mg days orbd forx >5 -310 days days after or defervescencefor > 3 days occurs after defe(feverrvescence should usually occurs .resolve within 72 hours of treatment initiation). Pregnant(Alternative) women Ciprofloxacin or allergy/intolerance 500mg bd to xdoxycycline: 5-10 days POor azithromycinfor > 3 days 500mg after asdefe a rsinglevescence dose occurs. Pregnant women or allergy/intolerance to doxycycline: PO azithromycin 500mg Preventionas a single and dose Control. Urban and domestic rat control. Prevention Protective and clothing Control from occupational exposure to rat fleas or mites in long grUrbanass. and domestic rat control. InsectProtective repellents clothing and from miticides occupational i.e. N,N -diethylexposure-3- methylbenzamideto rat fleas or mites (DEET) in long are effectivegrass. when applied to both clothing and skin. Insect repellents and miticides i.e. N,N-diethyl-3-methylbenzamide (DEET) are Referenceseffective when applied to both clothing and skin. 1. Ong AK, Tambyah PA, Ooi S et al. Endemic typhus in Singapore—a re-emerging infectious Referencesdisease? Singapore Med J. 2001; 42:549-52 2. Chen MI, Chua JK, Lee CC et al. Epidemiological, clinical and laboratory characteristics of 19 1. Ong AK, Tambyah PA, Ooi S et al. Endemic typhus in Singapore—a re-emerging infectious serologically confirmed rickettsial disease in Singapore. Singapore Med J. 2001; 42:553-8 disease? Singapore Med J. 2001; 42:549-52 3. Civen R, Ngo V. Murine typhus: An unrecognised suburban vector borne disease. Clin Infect Dis. 2. Chen MI, Chua JK, Lee CC et al. Epidemiological, clinical and laboratory characteristics of 19 2008;46:913-8. serologically confirmed rickettsial disease in Singapore. Singapore Med J. 2001; 42:553-8 4. Kim YS, Lee HJ, Chang M et al. Scrub typhus during pregnancy and its treatment: a case series and 3. Civen R, Ngo V. Murine typhus: An unrecognised suburban vector borne disease. Clin Infect Dis. review of the literature. Am J Trop Med Hyg 2006;75:955-9 2008;46:913-8. 4. Kim YS, Lee HJ, Chang M et al. Scrub typhus during pregnancy and its treatment: a case series and review of the literature. Am J Trop Med Hyg 2006;75:955-9 132 132 VIRAL HEPATITIS Causative Agent VIRAL HEPATITIS Hepatovirus (hepatitis A), orthohepadnavirus (hepatitis B), hepacivirus (hepatitis CCausative), deltavirus Agent (hepatitis D) and hepevirus (hepatitis E). Hepatovirus (hepatitis A), orthohepadnavirus (hepatitis B), hepacivirus (hepatitis IncubationC), deltavirus Period (hepatitis D) and hepevirus (hepatitis E). See Table. Incubation Period InfectiousSee Table. Period See Table. Infectious Period TransmissionSee Table. See Table. Transmission Epidemiology See Table. Hepatitis A, B, C and E are endemic in Singapore. Epidemiology AHepatitis total of A, 253 B, casesC and ofE areserologically endemic in confirmed Singapore. acute viral hepatitis were reported in 2009. Of these, 111 (44%) were imported. There were 89 cases of hepatitis A (35%),A total 69of 253cases cases of hepatitis of serologically B (27%), confirmed 5 cases of acute hepatitis viral C hepatitis (2%) and were 90 reportedcases of hepatitisin 2009. EOf (36%). these, No111 deaths (44%) were were reported. imported. There were 89 cases of hepatitis A (35%), 69 cases of hepatitis B (27%), 5 cases of hepatitis C (2%) and 90 cases of Clinicalhepatitis FeaturesE (36%). No deaths were reported. Fever Clinical Anorexia, Features nausea, vomiting RightFever hypochondrial pain JaundiceAnorexia, nausea, vomiting DarkRight urine,hypochondrial pale stools pain HepatomegalyJaundice Dark urine, pale stools See TableHepatomegaly for description of sequelae. InvestigationsSee Table for description of sequelae. Common biochemical abnormalities shared by the viral hepatitides: Investigations Leucopenia Common Urine biochemical urobilin, urobilinogen abnormalities shared by the viral hepatitides: RaisedLeucopenia serum bilirubin and transaminase levels (ALT > AST) RaisedUrine urobilin, gamma- urobilinogenGT Raised serum bilirubin and transaminase levels (ALT > AST) Raised gamma-GT 133 133 Investigations (See Table) . Hepatitis A: IgM antibodies become detectable when jaundice develops Investigationsand persist (Seefor approximately Table) 3 months. Hepatitis B:A: InIgM acute antibodies hepatitis become B, HBsAg detectable is present when in serum. jaundice However, develop its isand also persist present for approximately in long-term 3carriers months. of HBV. The diagnosis of acute . diHepatitissease is B: confirmed In acute hepatitisby demonstrating B, HBsAg IgM is presentanti-HBc in serum.antibody However, in serum. it Thisis also appears present 2 weeksin long after-term HBsAg carriers and of disappearsHBV. The adiagnosis few months of acuteafter uncodiseasemplicated is confirmed infection. by demonstrating IgM anti-HBc antibody in serum. HCV:This appears Diagnosis 2 weeks depends after