Kidney tissue, using a silver staining technique, revealing the presence of Leptospira bacteria Diffuse lungs bleeding due to<unk>  infection. Laboratory tests For those who are infected, a complete blood count may show a high white cell count and a low platelet count. When a low haemoglobin count is present together with a low white cell count and thrombocytopenia, bone marrow suppression should be considered. Erythrocyte sedimentation rate and C-reactive protein may also be elevated. The kidneys are commonly involved in<unk> . Blood urea and creatinine levels will be elevated.<unk>  increases potassium excretion in urine, which leads to a low potassium level and a low sodium level in the blood. Urinalysis may reveal the presence of protein, white blood cells, and microscopic haematuria. Because the bacteria settle in the kidneys, urine cultures will be positive for<unk>  starting after the second week of illness until 30 days of infection. For those with liver involvement, transaminases and direct bilirubin are elevated in liver function tests. The Icterohaemorrhagiae serogroup is associated with jaundice and elevated bilirubin levels. Hemolytic anemia contributes to jaundice. A feature of<unk>  is acute haemolytic anaemia and conjugated hyperbilirubinemia, especially in patients with glucose-6-phosphate dehydrogenase deficiency. Abnormal serum amylase and lipase levels (associated with pancreatitis) are found in those who are admitted to hospital due to<unk> . Impaired kidney function with creatinine clearance less than 50 ml/min is associated with elevated pancreatic enzymes. For those with severe headache who show signs of meningitis, a lumbar puncture can be attempted. If infected, cerebrospinal fluid (CSF) examination shows lymphocytic predominance with a cell count of about 500/mm3, protein between 50 and 100 mg/ml and normal glucose levels. These findings are consistent with aseptic meningitis. Serological tests Rapid detection of Leptospira can be done by quantifying the IgM antibodies using ELISA. Typically, L. biflexa antigen is used to detect the IgM antibodies. This test can quickly determine the diagnosis and help in early treatment. However, the test specificity depends upon the type of antigen used and the presence of antibodies from previous infections. The presence of other diseases such as Epstein-Barr virus infection, viral hepatitis, and cytomegalovirus infection can cause false-positive results. Other rapid screening tests have been developed such as dipsticks, latex and slide agglutination tests. The microscopic agglutination test (MAT) is the reference test for the diagnosis of<unk> . MAT is a test where serial dilutions of patient sera are mixed with different serovars of Leptospira. The mixture is then examined under a dark field microscope to look for agglutination. The highest dilution where 50% agglutination occurs is the result. MAT titres of 1:100 to 1:800 are diagnostic of<unk> . A fourfold or greater rise in titre of two sera taken at symptoms' onset and three to 10 days of disease onset confirms the diagnosis. During the acute phase of the disease, MAT is not specific in detecting a serotype of Leptospira because of cross-reactivity between the serovars. In the convalescent phase, MAT is more specific in detecting the serovar types. MAT requires a panel of live antigens and requires laborious work. Molecular tests Leptospira DNA can be amplified by using polymerase chain reaction (PCR) from serum, urine, aqueous humour, CSF, and autopsy specimens. PCR can detect Leptospira DNA in blood even before the antibody response develops. As PCR detects the presence of Leptospira DNA, it is useful even after antibiotic treatment has started. Imaging In those who have lung involvement, a chest X-ray may demonstrate diffuse alveolar opacities. Diagnostic criteria In 1982, the World Health Organization (WHO) proposed the Faine's criteria for the diagnosis of<unk> . It consists of three parts: A (clinical findings), B (epidemiological factors), and C (lab findings and bacteriological data). Since the original Faine's criteria only included culture and MAT in part C, which is difficult and complex to perform, the modified Faine's criteria was proposed in 2004 to include ELISA and slide agglutination tests which are easier to perform. In 2012, modified Faine's criteria (with amendment) was proposed to include shortness of breath and coughing up blood in the diagnosis. In 2013, India recommended modified Faine's criteria in the diagnosis of<unk> .
Leptospirosis
Rickettsiosis
Bartonellosis
Dengue fever
Typhoid fever
Malaria
Blackwater fever
Murine typhus