CD Alert Monthly Newsletter of National Centre for Control, Directorate General of Health Services, Government of India

May - July 2009 Vol. 13 : No. 1 SCRUB & OTHER RICKETTSIOSES

it lacks lipopolysaccharide and peptidoglycan RICKETTSIAL and does not have an outer slime layer. It is These are the diseases caused by rickettsiae endowed with a major surface protein (56kDa) which are small, gram negative bacilli adapted and some minor surface protein (110, 80, 46, to obligate intracellular parasitism, and 43, 39, 35, 25 and 25kDa). There are transmitted by arthropod vectors. These considerable differences in virulence and organisms are primarily parasites of arthropods antigen composition among individual strains such as lice, , ticks and , in which of O.tsutsugamushi. O.tsutsugamushi has they are found in the alimentary canal. In many serotypes (Karp, Gillian, Kato and vertebrates, including humans, they infect the Kawazaki). vascular endothelium and reticuloendothelial GLOBAL SCENARIO cells. Commonly known rickettsial disease is . Geographic distribution of the disease occurs within an area of about 13 million km2 including- The family Rickettsiaeceae currently comprises Afghanistan and Pakistan to the west; of three genera – , and to the north; Korea and Japan to the northeast; Ehrlichia which appear to have descended Indonesia, Papua , and northern from a common ancestor. Former members Australia to the south; and some smaller of the family, , which causes islands in the western Pacific. It was Q and Rochalimaea quintana causing first observed in Japan where it was found to have been excluded because the be transmitted by mites. The disease was, former is not primarily arthropod borne and therefore, called tsutsugamushi (from tsutsuga the latter is not an obligate , meaning dangerous and mushi meaning being capable of growing in cell-free media, insect or ). This is found only in areas besides being different in genetic properties. with a suitable climate, plenty of moisture and Scrub typhus will be dealt in detail. scrub vegetation. Recently, rickettsioses has SCRUB TYPHUS been an emerging disease along the Thai border. There are reports of CAUSATIVE AGENT emergence of scrub typhus in Maldive Islands and Micronesia. Scrub typhus (Chigger borne typhus, Tsutsugamushi fever) is caused by Orientia INDIAN SCENARIO tsutsugamushi. Orientia is a small (0.3 to 0.5 by 0.8 to 1.5 µm), gram negative bacterium of In India, scrub typhus has been reported from the family . It differs from the Rajasthan, Jammu & Kashmir and Vellore. In other members in its genetic make up and in addition, few cases have been tested positive the composition of its cell wall structure since for IgM antibodies for scrub typus from Sikkim, 1 Darjeeling, Nagaland & Manipur (unpublished morning, chiggers can be collected from the data). In a study conducted from July through body of the sentinel animals. The mites can October 2004 in Himalayas, among several be preserved in 70% alcohol till they reach cases of acute febrile illness of unknown origin, laboratory for identification. Chigger index O.tsutsugamushi was identified as causative (average number of chiggers infesting a single agent by microimmunofluorescence and PCR. host) of > 0.69 (critical value) is an indicator In an entomolgic study in Himachal Pradesh, for implementation of vector control measures. vector species Leptotombidium deliense and Gahrliepia spp. were recorded. Habitats favorable for disease transmission Scrub typhus, originally found in scrub jungles, DISEASE TRANSMISSION has also been identified in a variety of Scrub typhus is transmitted by the mite other habitats, such as sandy beaches, Leptotrombidium deliense. The vector mites mountain deserts and equatorial rain forests. inhabit sharply demarcated areas in the soil where the microecosystem is favourable (mite islands). Human beings are infected when they Incubation Period: 1 – 3 weeks. trespass into these mite islands and are bitten by the mite larvae (chiggers). The mite feeds CLINICAL PICTURE on the serum of warm blooded animals only  once during its cycle of development, and adult A Papule develops at the site of inoculation. mites do not feed on man. The microbes are  The papule ulcerates and eventually heals transmitted transovarially in mites. Scrub with development of a black . typhus normally occurs in a range of  General symptoms are sudden fever mammals, particularly field mice and rodents. (>40ºC [104ºF]) with relative bradycardia, The L.deliense group of vector mites are widely severe , apathy, , distributed all over the country coexisting generalized , photophobia primarily with rodents and other small and a dry . mammals. On the body of small mammalian  Approximately one week later, a spotted and hosts, the chiggers attach in clusters on the then maculopapular rash appears first on tragus of the ear, the belly and on the thighs. the trunk and then on the extremities and The Leptotrombidium mites, on the host, blenches within a few days. may appear orange or pink. The typical vector  Complications are interstitial L.deliense is generally found associated with (30 to 65% of cases), either established forest vegetation or and . secondary vegetation after clearance of forest areas. This species is generally abundant on  Symptoms generally disappear after two grasses and herbs where bushes are scarce. weeks even without treatment. Sentinel animals can also be used for collection  In severe cases with pneumonia and of trombiculid mites from the field. These myocarditis, the mortality rate may reach animals are generally white laboratory mice or 30%. kept in small cages containing food and water and placed in the field overnight to attract DIAGNOSIS chiggers. Chiggers can also be collected from field directly on human beings, by walking in Routine laboratory tests are unlikely to be the field after wearing stockings. The following diagnostic for any rickettsial diseases.

2 Common clinical manifestations of the Rickettsial Diseases

Scrub Typhus axillary eschar Maculopapular rash on back of a case of scub typhus

However, investigation may reveal Laboratory diagnosis early lymphopenia with late lymphocytosis. Scrub typhus may be diagnosed in the laboratory Albuminuria is a common laboratory by: finding. Thrombocytopenia is observed in more (i) isolation of the organism than half of the patients with (ii) typhus. (iii) molecular diagnosis (PCR). 3 Collection, storage & transportation of  Label all specimens accurately and send specimen all pertinent information to laboratory which will help in better interpretation of the The collection, transportation and storage of laboratory findings. specimens are extremely vital steps in laboratory diagnosis and hence, must be undertaken with Isolation of the organism utmost care. As rickettsiae are highly infectious and have Specimen caused several serious and fatal infections among laboratory workers, it comes under Risk  Serum Group 3 organisms. Isolation should be done in  Blood collected in tubes containing EDTA laboratories equipped with appropriate safety or Sodium citrate provisions preferably Biosafety level-3 labora- tory following strict biosafety precautions.  Blood clot Rickettsia may be isolated in male guinea pigs Blood collection in tubes and vials or mice; yolk sac of chick embryos; vero cell line or MRC 5 cell lines from patients in early  Aseptically collect 4-5 ml of venous blood. phase of the disease. Egg and animal inocula-  Allow blood to clot at room temperature, tion methods have been replaced by faster and centrifuge at 2000 rpm to separate serum. more sensitive cell cultures. Rickettsiae grow well in 3-5 days on Vero cell and MRC 5 cell  Collect the serum in sterile dry vial. coverslip cultures and can be identified by im- munofluorescence using group and strain spe-  Fix the cap with adhesive tape, wax or other cific monoclonal antibodies. sealing material to prevent leakage during transport. Serological diagnosis

 Use adhesive tape marked with pencil, Diagnosis of the etiology of rickettsial diseases indelible ink, or a typewritten self adhesive can be accomplished most easily and rapidly label to identify the container. The name of by demonstrating a significant increase in anti- the patient, identification number and date of bodies in the serum of the patient during the collection must be indicated on the label. course of infection and convalescence. Several serological tests are currently available for the Do’s/Don’ts while collecting specimen: diagnosis of rickettsial diseases like Weil-Felix  Collect sufficient quantity of specimen Test (WFT), Indirect Immunoflourescence (IIF), Enzyme linked Immunosorbent assay (ELISA)  Avoid contamination by using sterile etc. Although many techniques have been used equipment and aseptic precautions. successfully for rickettsial sero diagnosis, rela- tively few are used regularly by most laborato-  Despatch the specimen immediately to ries. BSL-3 Lab is not required for performing laboratory at 2-8ºC (ice box) as soon as serological tests. possible. Weil-Felix Test (commonly used test)  Don’t freeze whole blood as haemolysis may interfere with serology test results. The Weil-Felix test is helpful in establishing presumptive diagnosis in diseases caused by  In case the delay is inevitable, keep the members of typhus and groups of specimen at + 4ºC in a refrigerator. Rickettsiae. The interpretation of Weil-Felix test

4 is given in table 1. Molecular diagnosis – PCR

Table 1 : Weil-Felix Test For PCR, blood sample is collected in tubes containing EDTA or sodium citrate. However, OX 19 OX 2 OXK blood clot, whole blood or serum can also be used for the detection of O.tsutsugamushi, ++++ + 0 R.rickettsii, R. typhi and R.prowazekii organisms by PCR test. Brill Zinsser disease ++++ + 0 Facilities for laboratory diagnosis of Rickettsial ++++ + 0 diseases are available at National Centre for Disease Control, Delhi where samples can be Scrub typhus 0 0 +++ sent for confirmation.

RMSF ++++ + 0 TREATMENT

Other tick borne + ++++ 0 Prompt institution of effective therapy infection against rickettsiae is the single most effective measure for preventing morbidity and mortality Indian tick typhus + ++++ 0 due to rickettsial diseases. Anti rickettsial therapy improves the outcome of all rickettsioses, with The sensitivity and specificity of the Weil-Felix the occasional exception of fulminate or test is reported to be low as compared to the complicated cases of RMSF, epidemic typhus specific serological tests for detection of IgM and scrub typhus where the illness is no longer antibodies. However, comparative evaluation of susceptible to intervention. If the illness is severe, Weil-Felix test and IgM ELISA for diagnosis of the cardiac, pulmonary, renal, and central Scrub Typhus carriedout at NCDC, showed that nervous systems should be assessed and Weil Felix test is equally sensitive with specific- additional measures instituted to prevent ity of 89%. complications.

Indirect Immunofluorescent antibody (IFA) and remain the test only proven therapy for the rickettsial diseases. in a dose of 100 mg twice daily for IFA is used as a reference technique; however, 7-15 days or Chloramphenicol 500 mg four availability and cost are major constraints and times a day PO for 7-15 days (for children 150 is not available in most of the laboratories. mg/kg/day for 5 days) is recommended. Enzyme linked Immunosorbent Assay Tetracyclines may cause discoloration of teeth, (ELISA) hypoplasia of the enamel, and depression of skeletal growth in children; the extent of ELISA techniques, particularly immunoglobulin discolouration is directly related to the number M (IgM) capture assays, are probably the most of courses of therapy received. sensitive tests available for rickettsial diagnosis, Therefore, tetracycline should not be used for and the presence of IgM antibodies, indicate children under 8 years of age and for pregnant recent infection with rickettsial diseases. In women. cases of infecton with O.tsutsugamushi, a significant IgM antibody titer is observed at the PREVENTION AND CONTROL end of the first week, whereas IgG antibodies The mite vectors of scrub typhus are especially appear at the end of the second week. amenable to control because they are often

5 found in distinct areas (Typhus Island). infection but not the pubic . The lice become infected by feeding on rickettsiaemic  These foci can be eliminated by treating patients. The rickettsiae multiply in the gut of the ground and vegetation with residual the lice and appear in the faeces in 3-5 days. insecticides, reducing rodent populations, Lice succumb to the infection within 2-4 weeks, and destroying limited amounts of local remaining infective till they die. They can transmit vegetation. the infection after about a week of being infected.  Persons who cannot avoid infested terrain Transmission should wear protective clothing, impregnate their clothing and bedding with a mitecide (e.g. Lice may be transferred from person to person. benzyl benzoate) and apply a mite repellent, Being sensitive to temperature changes in the diethyltoluamide, to exposed skin. host, they leave the febrile patient or the cooling Chemoprophylaxis should also be carcass and parasitise other persons. Lice considered. defecate while feeding. Infection is transmitted when the contaminated louse faces is rubbed  In a controlled trial, the weekly through the minute abrasions caused administration of 200 mg doxycycline by scratching. Occasionally, infection may also decreased the incidence of clinical illnesses be transmitted by aerosols of dried louse faces but not of inapparent infection. through inhalation or through the conjunctiva.  An effective for humans has not Incubation period: 5 - 15 days. been developed till now, mainly due to serotypic heterogeneity of the organism. Clinical Presentation

OTHER RICKETTSIAE INFECTIONS  The disease starts with fever and chills.  EPIDEMIC TYPHUS A characteristic rash appears on the fourth or fifth day, starting on the trunk and spreading Epidemic typhus (Louseborne typhus, Classical over the limbs but sparing the face, palms typhus, Gaol fever) has been one of the great and soles. scourges of mankind, occurring in devastating  Towards the second week, the patient during times of war and famine. The becomes stuporous and delirious. The disease has been reported from all parts of the name typhus comes from the cloudy state world but has been particularly common in of consciousness in the disease. The case Russia and . During 1917-1922, fatality may reach 40% and increases with there were some 25 million cases in Russia, age. with about three million deaths. In recent times, the main foci have been Eastern Europe, Africa, In some who recover from the disease, the South America and Asia. In India, the endemic rickettsiae may remain latent in the lymphoid spot is Kashmir. tissues or organs for years. Such latent infection may, at times, be reactivated leading to The causative agent of epidemic typhus is recrudescent typhus or Brill Zinsser disease. R.prowazekii, named after von Prowazek. Brill noticed a mild, sporadic, typhus-like disease Humans are the only natural vertebrate hosts. in New York among Jewish immigrants from Natural infection in flying squirrels has been southeastern Europe. Zinsser isolated reported from South- eastern USA. The human R.prowazekii from such cases and proved that , Pediculus humanus corporis, is the they were recrudescences of infections vector. The head louse may also transmit the acquired many years previously.

6 ENDEMIC TY\PHUS

Endemic typhus (Murine typhus) is a milder disease than epidemic typhus. It is caused by R.typhi which is maintained in nature as a mild infection of rats, transmitted by the rat , Xenopsylla cheopis. The rickettsia multiplies in the gut of the flea and is shed in its faeces. The flea is unaffected but remains infectious for the rest of its natural span of life. Humans acquire the disease usually through the bite of infected fleas, when their saliva or faeces is rubbed in or through aerosols of dried faeces. Ingestion of food recently contaminated with infected rat urine Eschar of tick bite over the left side of the abdomen or flea faeces may also cause infection. Human a case of endemic typhus or with a culture of infection is a dead end. Man to man transmission R.typhi, they develop fever and a characteristic does not occur. In India, endemic typhus has scrotal inflammation. The scrotum becomes been reported from Pune, Lucknow, enlarged and the testes cannot be pushed back Mysore, Kolkata, Golkunda, Karnal, Rewari into the abdomen because of inflammatory and Kashmir. adhesions between the layers of the tunica vaginalis. This is known as the Neil-Mooser or Clinical presentation the tunica reaction. The Neil-Mooser reaction is  Endemic typhus resembles many other negative with R. prowazekii. illnesses and very few patients are provisionally diagnosed correctly. SPOTTED FEVER GROUP

 Initially, the patient can present with They are all transmitted by ticks, except R.akari, headache, fever and rash. This is seen only which is mite borne. Rickettsiae of this group in 12% of cases. possess a common soluble antigen and multiply in the nucleus as well as in the cytoplasm of  Rash develops in 54% of patients some time host cells. Many species have been recognized during the course of illness. in this group.  , , diarrhoea and abdominal pain suggest gastrointestinal diseases while Organism Disease cough and abnormal chest radiograph suggests pneumonia or bronchitis. R.rickettsii Rocky Mountain spotted fever  Severe illness including seizures, coma, R.siberica Siberian tick typhus renal insufficiency and respiratory failure are seen in approximately 10% of cases, R.conori Indian, Mediterranean, Kenyan only 1% of cases are fatal. and South African tick typhus R.typhi and R.prowazekii are closely similar but may be differentiated by biological and R.australis immunological tests. When male guinea pigs are inoculated intraperiotoneally with blood from R.japonica Oriental spotted fever

7 The rickettsiae are transmitted transovarially in country namely Allahabad, Narsapatnam, ticks, which therefore act as both vectors and Ratlam, Secunderabad, Trichinapally, reservoirs. The infection may be transmitted to Bangalore, Jhansi, Darjeeling, Pune and vertebrate hosts by any of the larval stages or Lucknow. The tick sp. Rhipicephalus by adult ticks. Ticks are not harmed by the sanguineus is the most important vector and is rickettsiae and remain infected for life. The generally found infesting dogs all over. rickettsiae are shed in tick faeces but Some species of Haemaphysalis and transmission to human beings is primarily by Hyalomma ticks may also transmit the infection. bite, as the rickettsiae also invade the salivary glands of the ticks. All rickettsiae of this The incubation period ranges from 2 to 7 days. group pass through natural cycles in domestic In >50% of the patients, a primary lesion with and wild animals or birds. central necrosis (eschar) appears at the site of the tick bite. The lesion is covered with a brownish ROCKY MOUNTAIN SPOTTED FEVER black scab (tachy noire) and may ulcerate. Recall of a tick bite cannot always be elicited Rocky Mountain Spotted Fever (RMSF) is the from the patient. Regional lymphandenitis is most serious type of spotted fever and is the common. The fever lasts for 1 to 2 weeks and first to have been described. It is prevalent in is accompanied by headache, , many parts of North and South America and is and a generalized maculopapular rash transmitted by and which develops between the third and fifth days related species of ticks. of illness or which may not appear. It disappears TICK TYPHUS (INDIAN TICK TYPHUS) at the time of defervescence. Alterations in cytokine profiles, hypercoagulability and deep Tick typhus, in several parts of Europe, Africa venous thrombosis may occur. In severe cases and Asia is caused by R.conori, strains of which – particularly in elderly patients and those with isolated from the Mediterranean region, Kenya, diabetes mellitus, alcoholism or heart failure – South Africa and India are indistinguishable. The meningoencephalitis with coma and seizures species is named after Conor, who provided the and/or disseminated of internal organs first description of the Mediterranean disease. (e.g. in the heart, lungs, kidneys, and Tick typhus was first observed in India in the pancreas) are observed. The mortality rate is 1 foothills of the Himalayas. Subsequently, the to 5% but is higher among patients with severe disease was reported from many parts of the cases.

...about CD Alert

CDAlert is a monthly newsletter of the National Centre for Disease Control (NCDC) (formerly known as NICD), Directorate General of Health Services, to disseminate information on various aspects of communicable diseases to medical fraternity and health administrators. The newsletter may be reproduced, in part or whole, for educational purposes.

Chief Editor: Dr. R. K. Srivastava Editorial Board: Dr. Shiv Lal, Dr. R. L. Ichhpujani, Dr. Shashi Khare, Dr. A. K. Harit Guest Editor (Authors): Dr. D. Bhattacharya, Dr. Veena Mittal, Dr. Naveen Gupta, Dr. A.C. Dhariwal, Dr. Arti Bahl Publisher: Director, National Centre for Disease Control, 22 Shamnath Marg, Delhi 110 054 Tel: 011-23971272, 23971060 Fax : 011-23922677 E-mail: [email protected] and [email protected] Website: www.nicd.nic.in

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