After a hot summer, the arrival on rains in Monsoon are really welcome. But in urban areas while rain does bring down the temperature, it also leads to flooding and it is not infrequent that we have to wade through ankle to knee deep water to reach our house, office or school. Rain bring not only mosquitoes that can transmit Malaria, Dengue, Chikungunya and Japanese Encephalitis but also Ticks that transmits can transmit Scrub typhus. To add to our woes, wading through water contaminated with urine of rodents, cows, dogs etc exposes us to another infection.
Leptospirosis is primarily a disease of animals, occasionally infect humans. It is caused by pathogenic spirochete of the genus leptospira that traditionally consist of two species, Leptospira interrogans and Leptospira biflexa. The former includes all pathogenic serovars and the later includes the saprophytic strains. Leptospira is shed in the urine of infected animals and even though person to person transmission of infection has not been documented, we can acquire the infection via wading through contaminated water.
Human infection usually results from exposure to environmental sources, such as animal urine, contaminated water or soil or infected animal tissues. Portals of entry includes cuts or abraded skin, mucous membranes or conjunctiva. The infection may rarely be acquired by ingestion.
Clinical course of leprospira is variable. Most cases are generally mild and self limited, occurring 5 to 14 days after exposure, but severe cases with kidney, liver or CNS involvement, leading to death have been reported. Conjunctival suffusion is an important but frequently overlooked sign. As it is not a common findings in other infectious diseases, it presence in a patient with febrile illness should raise the possibility of leptospira infection. Nonproductive cough, nausea, vomiting and diarrhea occurs in about 50%. Muscle tenderness, splenomegaly, lymphadenopathy, pharyngitis, muscle rigidity or skin rash may occur in 7 to 40 percent of patients. Less common symptoms include arthralgia, bone pain, sore throat and abdominal pain.
Leptospirosis may be complicated by jaundice and renal failure (Weil’s disease), pulmonary haemorrhage, acute respiratory distress syndrome (ARDS), uveitis, optic neuritis, peripheral neuropathy, myocarditis and rhabdomyolysis.
Routine laboratory tests maybe nonspecific. White blood cells counts are generally less than 10,000/mm3 but may range between 3000 to 26,000 /mm3. Thrombocytopenia is common. Hyponetremia is common in severe leptospirosis as the bacteria has the capacity to act directly on electrolyte transport mechanisms, including deranged of sodium and potassium. There is hypokalemia and sodium wasting.
Urinalysis frequently shows proteinuria, pyuria, granular casts and occasional hematuria. Elevated creatinine kinase is observed in 50% of patients. Approximately 40% have minimal to moderate elevation of hepatic transaminases. Jaundice my be observed in severe cases. CSF may show lymphocytic or neutrophilic pleocytosis with minimal to moderately elevated protein concentrations and normal glucose concentration.
Chest radiography may demonstrate small nodular densities, which may progress to confluent consolidation or a ground glass appearance. Findings associated with adverse outcomes include oliguria, WBC count above 12,900 /mm3, repolarization abnormalities on ECG and alveolar infiltrates on chest X Ray.
There are a number of modalities available for diagnosis of leptospira infection, but the method recommended in National Guidelines : Diagnosis, Case Management, Prevention and Control of Leprospirosis 2015, issued by National Centre for Disease Control, Govt of India suggests the following:
PathkindLabs would like to offer a comprehensive Leptospira profile to alert the clinician not only about the presence or absence of Leptospira infection but also its effects on vital organs: