Leptospira interrogans serovars and (Serov icterohaemorragiae, hebdomadis, autumnalis, canicola, hyos, bataviae javanica, pomona, ballum, grypothyphosa, panama, hardjo, celledoni, ....) - Cultivation; Microagglutination antibodies (MAT); molecular diagnosis (PCR); Molecular identification of serovars (sequencing). Current importance of bats.
Leptospira is a genus of bacteria in the order of spirochetal, family Leptospiraceae, with a worldwide distribution, except Antarctica. Most leptospires are hydrophilic, so high humidity and neutral pH are essential for survival. As a result, this organism is localized mainly in stagnant waters, marshes, lakes and ponds. Leptospires are flexible and helical spirochetes of 0.1 .mu.m diameter and 6-20 microns in length, with ends incurved hook. It has a similar to Gram - negative bacteria, consisting of a cytoplasmic membrane and an outer membrane cell envelope. 200 described Leptospira antigenic varieties (serovars).
The life cycle of this organism involves a host where it multiplies. Most serovars have the primary reservoir for wild mammals and from them, and kidneys are infected domestic mammals such as rodents and dogs are colonized. Leptospira is transmitted in nature in its animal reservoir through environmental contamination by contact with moist soil or water contaminated with urine or tissues of infected animals vegetation; through direct contact with mucous membranes or tissues of infected animals; or through the bite of infected animals. In people, infection with this organism occurs through direct contact with urine or tissues of infected animals and by water contaminated with urine of infected animals soils.
Among animals, Leptospira affects mainly rodents and dogs, although it can affect other mammals (pigs, cattle, and bats). In people causes Leptospirosis or Weil 's disease (severe form of leptospirosis), a disease zoonotic worldwide distribution with high incidence rates in tropical and subtropical areas, having the highest incidence rates in South America and Australia. Most epidemiological studies have focused on domestic animals as reservoir hosts for human infection. In recent years, it has identified the bat as an important source of Leptospira epidemiological because of its abundance and spatial distribution in the environment of humans and pets. It must take into consideration that insectivorous bats are in proximity to the human population, where in lighted areas at night are easily affordable food, with an absence of predators areas. This increases the likelihood that the bats removed by excreta come into contact with people or pets. For this reason, they have done and published several epidemiological studies in areas with high incidence of leptospirosis, to determine the prevalence of infection in different species of bats among the more than 1,200 that are known throughout the world, having been found in some of the studied carriers of Leptospira spp bats. in Brazil, Peru, Australia, Madagascar, with some prevalences in some regions and bat species up to 35%. It has been found that bats are a reservoir mainly of Leptospira interrogans and Leptospira borgpetersenii and other species such as Leptospira kirschneri, and Leptospira fainei.
Leptospirosis has become a major health problem in rural and urban areas because of its high incidence and lethality. Leptospires immediately generate systemic infection with multiorgan involvement, due to its passage through tissue (possibly between intercellular junctions) and broadcast via blood , colonizing different organs such as the liver, kidney, heart, skeletal muscle and even the central nervous system. Once in the host organism, this bacterium produces a group of enzymes that degrade the extracellular matrix of tissues: collagenase and metalloprotease several hemolysins. In colonization, the bacterium produces two families of afimbricas adhesin. The first has three genes: LIGA ligB and ligC, BIG encoding proteins, involved in host pathogen interactions. The second family consists of three integrins (alpha protein), each with seven repeat sequences that apparently are involved in interactions with the ligand.
In people, leptospirosis has an incubation period of 7 to 14 days. Manifestations of Leptospira infection may start with a fever of sudden onset, major malaise, chills, headache, myalgia, conjunctival suffusion, diarrhea, and vomiting. In severe cases of leptospirosis ( Weil 's disease ) can be associated signs and symptoms such as jaundice intense bleeding skin (bleeding diathesis), acute renal failure and liver, heart, lung and digestive problems. In pregnant women, abortion, stillbirth, premature birth or congenital leptospirosis may occur. When consider the diagnosis must take into account that Leptospira is blood (leptospiremia) in the first 10 days of infection, which can be found cerebrospinal fluid from the tenth day (2nd week), and urine from the tenth day (preferably third week).
Recommended tests for diagnosis:
Diagnosis through microscopic examination of urine and other samples is highly unlikely.
The most common diagnoses are antibody detection by various methods, because when diagnosed clinically infection, enough time has elapsed for antibodies exist time. The specific method is the microscopic agglutination (MAT. Microaglutination Test).
Culturing can be performed in buffered saline solutions with a protein source (decomplemented serum of an animal) at room temperature for 7 to 15 days, observing the growth of leptospires by dark background.
Currently, molecular diagnostic methods (PCR) are considered the most suitable, being the most sensitive.
Tests in IVAMI:
- Antibody detection by agglutination (MAT Test: Test microagglutination).
- Molecular diagnosis (PCR), to detect DNA of Leptospira.
- For detection of antibodies: blood serum separated (1 mL) obtained from the second week of the infection and preferably the third week. Antibodies decreases from the third month and persist after recovery.
- For culture: urine (1-5 mL), CSF in cases of meninges (minimum 1 mL), whole blood collected in EDTA or ACD (in phase leptospiremia -First 8 days after infection) (2 to 5 mL ).
- For molecular diagnostics: for the same samples indicated crop or antibodies.
- In the case of requiring investigate its presence in mammals that may be animal reservoirs of infection: kidney tissue (kidney).
Preservation and shipment of sample:
- Refrigerated (preferred) for less than 2 days (for antibodies, culture and / or molecular diagnostics).
- Frozen: over 2 days (serum antibodies, or molecular diagnostic samples -PCR-).
- Microagglutination antibodies (MAT): 5 - 7 days.
- Cultivation: 6 weeks with peródica observation by darkfield microscopy.
- Molecular diagnosis (PCR): 24 to 48 hours.
Cost of the test: