Leptospira interrogans

Epidemiology : reported in Madras in 1996

Transmission : reservoir : Bandikota bengalensis

Epidemiology :

USA : chronology of notable outbreaks of leptospirosis

1931 : 7 cases acquired while swimming in a creek in Philadelphia (contamination by rat urine)
1940 : 35 cases acquired while swimming in a creek in Georgia (contamination by a dead cow)
1942 - 24 cases acquired while swimming in a pool in Wyoming.
1950 - 50 cases acquired while swimming in a creek in Alabama (pig contamination suspected).
1950 - 9 cases acquired from a pet dog in North Dakota.
1952 : 26 cases acquired while swimming in a creek in Georgia (dog contamination implicated)
1956 - 3 cases acquired while swimming in a river in South Dakota.
1958 : 9 cases acquired while swimming in a stream in Florida (either cattle or pigs suspected)
1959 - 40 cases acquired while swimming in a stream in Iowa (cattle implicated).
1964 - 61 cases acquired while swimming in a canal in Washington (cattle suspected).
1971 - 7 cases acquired from pet dogs in Texas.
1972 - 9 cases acquired from a pet dog in Oregon.
1972 - 5 cases acquired from pet dogs in Missouri.
1975 - 7 cases acquired while swimming in a creek in Tennessee.
1985 - 4 cases acquired while boating in a creek in Missouri.
1987 - 8 cases acquired while swimming in a river in Hawaii (cattle suspected).
1991 - 5 cases acquired while swimming in a pond in Illinois.
1992 - 8 cases acquired while swimming in a waterfall in Hawaii.
1998 - 375 cases among Ironhorse Triathlon and Bally Total Fitness USTS Triathlon participants in Illinois and Wisconsin; 14 local residents (Illinois) were also found to be seropositive at the time. These events were associated with high attack rates among the participants: 11% in the Illinois-only participants, 5% in the Wisconsin-only participants, and 7% in athletes participating in both events^ref.
2000 - 68 clinical cases (0 fatal; including 32 laboratory confirmed cases) among American athletes competing at a racing competition in Sarawak, Malaysia [became ill on return home].

Africa :

Ethiopia : 47.5% of febrile outpatients who did not have malaria were seropositive for leptospirosis
seroprevalence rates for leptospirosis were 33% in Ghana and 18% in Nigeria

South America :

Peru : a study conducted in 2001 revealed that 0.7% of the population of Pampas San Juan are seropositive, 16.5% in rural communities (San Carlos, Moralillo and Buen Pastor) and 28% in Belen^ref. 29% of wild mammals in the region of Iquitos are infected with Leptospira species (1.5% with Leptospira interrogans) - 19% of rodents, 39% of marsupials and 35% of chiropters (1997 to 1998)^ref. Notable outbreaks: 1999 - An outbreak (72 cases) was reported among military recruits in the Amazon (Junin Department)^ref
Uruguay : in 2002 and 2003, an incidence of at least 7 confirmed cases/100 000 persons. They were mainly male rural workers, 20-40 years old, associated with bovine raising and dairy production

Australia : leptospirosis was first reported in Queensland Australia in 1934. According to the Australian Cummunicable Diseases Intelligence (CDI) 1999 report, there are an average of 50 to 120 reports of leptospirosis in Queensland per year. In the period Jan through May of 1998 there were 153 cases reported from Queensland of which 80% came from the far north of the state. Epidemiological investigations showed that the banana (agriculture), meatworker and farming industries accounted for > 30% of the reported cases. 75% of the cases were in 20-49 year old individuals, with school aged children (5-16%) representing 5% of the reported cases. Serovars identified during this period (with percent of total in parentheses) were: positive cultures - unknown (26.5), zanoni (20.0), hardjo (16.1), australis (10.3), szwajizak (6.5), pomona (5.9), kremastos (3.2), canicola (3.2), robinsoni (1.9), tarassovi (1.3), grippotyphosa (1.3), celledoni (1.3), ballum (1.3), medanensis (0.6), bulgarica (0.6). For more background on leptospirosis in Australia below are some selected references^{ref1,
ref2,
ref3,
ref4,
ref5,
ref6,
ref7}

Leptospirosis is not uncommonly spread through civilian or military activities in wet environments. The following 6 references illustrate outbreaks of the infection in military personnel around the world : U. S. army troops in the Canal Zone^ref, American soldiers in Vietnam^ref, United States Marine Corps personnel, Okinawa, Japan, 1975--1976^ref1,
ref2, Malaysian Armed Forces^ref, Peruvian military recruits^ref.

Proteomics :

outer membrane proteins (OMPs)

LipL21 (absent in in nonpathogenic L. biflexa)
LipL32
LipL41

Transmission : a zooanthroponosis ; primarily through percutaneous, oral or conjunctival routes after exposure to water contaminated with urine from infected Rodentia

(Rattus spp.

, Microtus agrestis , Clethrionomys glareolus , Myocastor coypus Molina ), Canis familiaris , Sus scrofa , Felis catus , Bos taurus , Equus caballus , and Ozotocerus bezoarticus . The combination of flooding and rodent urine are not always the main origin of leptospirosis. In general, in temperate regions domestic animals or livestock may be the usual source of infection^ref. Disease has been also reported in the following species: foxes, skunks, raccoons, opossums, sea lions, reptiles, frogs, field mice, voles, shrews, and hedgehogs. An infected animal's renal tubules harbor the bacteria and shed the organisms for months. The environment is contaminated with infected urine, and subsequent transmission often occurs by contact with water, food, or soil. In favorable conditions, leptospira can survive in fresh water for as many as 16 days and in soil for as many as 24 days. Direct contact with non-rodent animals such as Canis familiaris may also produce infection, as shown by an outbreak in suburban St. Louis, MO, USA, in 1973 in which dogs acquired leptospirosis from drinking water contaminated by rodent urine and subsequently directly transmitted the spirochete to children^ref. Leptospirosis has classically been thought of as an occupational zoonosis affecting agricultural workers, such as sugar cane cutters, rice field workers, farmers, veterinarians, abbattoir workers, farmers, and other individuals with direct animal contact. During rainy seasons, the number of cases increases dramatically.
=> leptospirosis : 2÷21 days (usually 7-12 days) incubation

asymptomatic (15-40%) : serologic evidence of past infection

symptomatic (60-85%)

anicteric leptospirosis / cane-cutter, cane-field, canicola, dog-days, field, harvest, rice-field, sugar cane fever / Stuttgart disease / 7 days fever / Hasami or Pomona fever (90%) : the more common and milder form; often is biphasic

first phase characterized by sudden onset of flu-like symptoms for 4÷10 days (high fever with chills, headache , cough and pulmonary chest pain, abdominal pain , nausea and vomiting , myalgia, hemorrhagic conjunctivitis (subconjunctival hemorrhages : 92%), photophobia , lymphadenitis , hepatomegaly, splenomegaly , exanthema, relapsing uveitis (2%; can develop early or late in the disease and has been reported as late as 1 year after initial illness. Iridocyclitis and chorioretinitis are other late complications that may persist for years. These symptoms first manifest 3 weeks to 1 month after exposure), diarrhea, nausea and vomiting , and abdominal pain ). In epidemic leptospirosis on the Indian subcontinent (Mumbai) and in the Americas (Nicaragua^ref, Brazil^ref), severe respiratory disease was found to be a prominent manifestation of the infection. The illness may resolve with no further manifestations; or, after 1÷3 afebrile and relatively asymptomatic days, recur with milder and more varied symptoms than in the first phase - except that intense headache poorly controlled by analgesics often heralds the onset of benign aseptic meningitis (from L.i. serovar canicola, icterohaemorrhagiae, grippotyphosa,pomona or tarassovi => young swineherd's disease, affecting those who work with swine or pork or come in contact with the urine of carriers) may occur for 2-3 days, but occasionally for 1-2 weeks. Mortality is extremely rare in the anicteric cases : death may arise from cardiocirculatory or acute renal failure .
mud, autumn, marsh, slime or swamp fever is leptospirosis occurring in the summer and late autumn in Germany and Russia transmitted by a field mouse, Microtus arvalis (common vole), and affecting workers in flooded fields or in swamps.

icteric leptospirosis / Landouzy-Larrey-Fiedler-Mathieu-Vasilev-Weil syndrome / hemorrhagic jaundice (10%, expecially from L.i. serovar icterohaemorrhagiae) : the more severe form, characterized by symptoms as described above (except not usually biphasic); after about 1 week, the development of acute renal failure , pulmonary complications (espiratory symptoms associated with pulmonary hemorrhage in Argentina^ref), jaundice , and/or hemorrhagic manifestations (hemorrhagic myocarditis ) => death.

nanukayami disease or fever / akiyami / 7-day or autumn fever / gikiyami : a leptospirosis marked by fever and jaundice , first reported in Japan; the animal host is the field vole, Microtus montebelli (Japanese grass vole)

Laboratory examinations : indirect diagnosis :

microscopic agglutination test (MAT) or Martin-Petitt reaction

slide microagglutination or Galton reaction

agglutinin absorption test (AAT)

Therapy : penicillins

or doxycycline

. Jarisch-Herxheimer reaction (JHR)

can occur. Early hemodialysis

to treat uremia.
Prevention : animal vaccination doesn't prevent carrier status. Killed vaccine

. Chemoprophylaxis has been shown to be effective for persons with potential risk for exposure, such as military troops traveling to endemic areas or vacationers engaging in aquatic recreation. Doxycycline

can be used; a USA Army study done in soldiers training in Panama in the fall of 1982 found that 200 mg of doxycycline taken once weekly prevented leptospirosis^ref, symptomatic or subclinical (serological conversion), with an efficacy of 95%^ref. However, it is not recommended for persons with long-term or repeated exposure and a more recent report from India^ref found that that same treatment statistically decreased clinical disease but did not prevent serologically proven, subclinical infection. The differences between the studies may well be the degree of risk, with the later study having a higher risk of exposure.
Experimental animal models : nefast crisis : the peculiar onset of severe and unaccountable symptoms in experimental icterogenous spirochetosis.
Web resources :