R Stephenson. Rickettsia in the Regiment
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JR Army Med Corps 1989; 135: 21-24 Case Report J R Army Med Corps: first published as 10.1136/jramc-135-01-06 on 1 February 1989. Downloaded from Rickettsia in the Regiment -Major R Stephenson MB, BS, DA, RAMC(V) Regimental Medical Officer, RHQ Royal Wessex Yeomanry, Cirencester, Gloucestershire _ SUMMARY: A case of Rocky Mountain Spotted Fever (RMSF) is described, together with other cases of pyrexia whose occurrence originally gave the impression of a significant outbreak of the disease in a TA regiment after annual training in the USA. The role of the RMO is considered in such circumstances. Introduction The human rickettsioses are represented world-wide, _ The Royal Wessex Yeomanry (RWxY) was formed in occurring sporadically, and only occasionally producing 1971 by the amalgamation of three county Yeomanry epidemics when conditions are favourable, such as in Regiments - the Royal Wiltshire Yeomanry, the Royal Naples in World War 11 when epidemic typhus was Gloucestershire Hussars and the Royal Devon transmitted by the louse because of poor hygienk Yeomanry . TA centres were established in the principal conditions. The geographical distribution and arthropod • towns of these three counties and in 1987 a composite vectors of the human disease are summarised in Table 1. squadron (Sqn) from these widely dispersed localities undertook an exchange exercise in the USA. Case Report For the duration of Exercise Mulberry Tree daily self 2021 by guest. Protected copyright. Exercise Mulberry Tree inspection for ticks was encouraged and a tick register The RWxY Sqn of 120 all ranks, joined a field exercise was maintained by the Squadron Combat Medical • of the 45th Infantry Brigade, Oklahoma Army National Technician. During the fortnight, 72 persons reported Guard (OKARNG) in June 1987. The OKARNG tick bites and the 'lone star' tick Amblyomma Training Area, Camp Gruber, is situated in the Cookson americanum, so called because of a white mark on the Hills on the eastern border of Oklahoma State. It scutum of the female, was identified. consists of dry grassland with areas of low deciduous Within a week ofreturning 8 Yeoman became ill with • woodland and smaller areas of swamp and damp pyrexial illnesses and consulted their family ground. The average daily temperature in June is in the practitioners. All were able to report the risks of mid to high 30's on the Celsius scale, and there is a high exposure to RMSF and all were investigated. Serum humidity. from all three counties was sent by the Public Health Before leaving, the RWx Y Sqn were brought to a high Service Laboratories to its Special Pathogens Reference level of physical fitness to reduce morbidity from the Laboratory at Porton Down in Wiltshire. A complete • marked climatic change. Briefing concerned the list of troops investigated was provided for the RMO, problems of climatic adaption, fluid intake and the risks and one case of RMSF was confirmed by the from snake and tick bites. The possibility of infection by Laboratory. a rickettsial organism was described, as RMSF is no LlCpl F, aged 23 years, presented to his family doctor longer confined to the Rocky Mountain area but is three days after returning to the UK with a twenty four • reported in practically all states of the USA, as well as hour history of headache, fever and a rash. He detailed Canada and parts of Central America. However, the his movements over the previous two weeks, and the fact http://militaryhealth.bmj.com/ highest incidence of 1000 cases between 1977 and 19801 that he had been bitten by two ticks. He was admitted to occurred in the "Old" South and Mid-West, including the District General Hospital (DGH) where examination the Carolinas, Virginia, Georgia, Maryland, Tennessee showed him to be generally well, but pyrexial (37.SOC) and, most important for Exercise Mulberry Tree, with no neck stiffness or photophobia. He had a • Oklahoma. minimally injected oropharynx with tonsillar RMSF was originally described in the nineteenth enlargement and lymphadenopathy in the left century in Montana, Idaho and Wyoming and was supraclavicular fossa and both inguinal regions. He also thought to follow tick bites in those individuals who were had an erythematous macular rash over his trunk, upper known to sleep on the ground whilst working in the arms and legs. There were no haemorrhagic lesions. developing Mid-West, such as brid§e and railroad On the day ofadmission his haemoglobin was 15.5 g/dl 9 - builders, carpenters and civil engineers. The American and his total white cell count was 3.4 x 10 /1. There was on September 26, pathologist HT Ricketts (1871-1910) first demonstrated also a slight thrombocytopenia (97 x 109/1). His rickettsial bodies as a cause for RMSF and described the rickettsial antibody titre by indirect haemaglutination was 3 wood tick as the route of transmission to the human . negative for typhus group and that for spotted fever group He died of Mexican typhus whilst investigating its cause was less than 1180. He was treated with oral tetracycline • and spread. (500mgs six hourly) and by the following day his 22 Rickettsia in the Regiment J R Army Med Corps: first published as 10.1136/jramc-135-01-06 on 1 February 1989. Downloaded from Table 1 Rickettsial Diseases • Disease Rickettsia sp. Geographic Arthropod Distribution Vector Reservoir Spotted Fever Group Rocky Mountain Spotted Fever R. rickettsii North, Central and Tick • parts of Southern America Fievre Boutonneuse R. conorii Mediterranean Tick Kenya tick typhus Europe, Africa, India, S. African tick fever Middle East • Indian tick typhus Queensland tick typhus R. australis Australia Tick North Asian tick typhus R. sibirica Siberia, Mongolia Tick • Rickettsial pox R. alcari America, Russia, Mite 2021 by guest. Protected copyright. Korea, parts of Africa RMSF-like R. canada North America Tick • Typhus Group Epidemic typhus R. prowazeki World-wide, mainly Louse S. America, Asia, Africa • Murine (endemic) typhus R. mooseri Worldwide Flea Scrub typhus R. tsutsugamushi Asia, Pacific Islands, Mite Japan, Australia Others • QFever Coxiella burnetii Worldwide None (human infection from dust inhalation) Trench Fever Rochalimaea quintana Rare Louse •http://militaryhealth.bmj.com/ I condition had improved sufficiently to allow discharge were seen by the RMO and a fading maculopapular rash • home. His rash faded over the next few days. observed. A confident diagnosis of rubella was His serology was repeated seventeen days after confirmed by raised rubella antibody titres. A third rash admission when the typhus group haemaglutination titre was reported to the RMO as being an excoriated rash remained negative but the spotted fever group titre was from insect bites. None of the other three cases had a now 11160. This titre rise had probably been attenuated rash; two presented with pyrexia, malaise and by the prompt tetracycline treatment, but it was generalised aches, but no firm diagnosis appeared to • considered significant enough to establish the diagnosis have been reached, and the last soldier presented with on September 26, ofRMSF. vertigo and was apyrrexial. His name did not appear on Of the remaining seven cases, four reported general the Squadron list but he had convinced his GP that he feelings of debility accompanied by a rash, two with had been at risk whilst exercising on Salisbury Plain with either myalgia or mild arthralgia. Two of these soldiers the UK exchange party of OKARNG! • R Stephenson 23 J R Army Med Corps: first published as 10.1136/jramc-135-01-06 on 1 February 1989. Downloaded from Discussion The "hard ticks", Ixodidae (Fig 1), are recognised as tfoth vectors and reservoirs of infections for several of the rickettsial diseases. RMSF is known to be spread by the wood tick Dermancentor andersoni and the dog tick Dermacentor variabilis as well as Amblyomma americanum. The brown dog tick Rhipicephalus • sanguineus is known to transmit RMSF and fievre boutonneuse, as well as other rickettsial diseases. In the spring and summer months a delay of only 45-90 minutes after attachment is required for the tick to be considered infectious and during that time the body becomes engorged with blood of the host, increasing the number • of rickettsia within the tick. It is also known that the excreta of ticks is infectious if rubbed in through abrasions in the skin. The clinical aspects of RMSF, such as malaise, headache, pyrexia and rash, appear after an incubation • period of 3-12 days and are a result of proliferation of rickettsiae in endothelial linings of small blood vessels, producing an inflammatory vasculitis. The rash, beginning in the extremities around the 3rd to 6th day, is Fig. 1. Hard Tick (Ixodidae) Body Parts, scutum 2021 by guest. Protected copyright. a flat pink lesion which fades on pressure. It starts on the and capitulum, total 4-6 mm long. palms, soles, forearms and lower legs and over the next • 48 hours spreads to the trunk and buttocks, giving a Reproduced by Qermission from BECK, J WALTER, deeper red maculopapular appearance as it ages. In and BARRETT-CONNOR, E: Medical Parasitology 1971; The C V Mosby Co., St Louis, MO., USA. untreated cases the rash may become frankly haemorrhagic and eccymotic, the end result of endoangiitis. A mortality of 20% should be expected in • untreated cases, mainly in the over SO year age group, as medical problems arise. The TA RMO, with soldiers a result of vascular collapse and circulatory failure. scattered over a wide area, is therefore at a disadvantage Neurological manifestation, such as hemiplegia and compared with his regular colleague in that he is unable coma, may indicate rickettsial encephalitis. to initiate or control the investigation of any illness Tetracycline, which is rickettsiostatic only, was contracted during the time abroad.