TTV can be found in many parts of the body, such as tissues, cells, and body fluids, except for red blood cells and platelets. It has been found in various bodily fluids like saliva, sweat, bile, semen, urine, feces, nasal and vaginal secretions, and scrapings from the back of the nose and throat. It multiplies in certain types of cells like mononucleocytes, liver cells, bone marrow cells, and certain blood cells, especially T lymphocytes. To diagnose a TTV infection, doctors can examine biopsy samples taken from the liver, lymph nodes, bone marrow, spleen, pancreas, lungs, and thyroid gland and run some tests like polymerase chain reaction (PCR) assays and immunoassays.
When the TTV virus multiplies and triggers the body’s immune response, it leads to the production of immunoglobulins, which are important for fighting against viruses. To determine the presence and quantity of antibodies against TTV in biological samples, immune assays are used. After TTV infection, the first antibodies to appear in the blood usually show up 10 to 21 weeks after infection, but then start to decrease and gradually disappear within 5 to 11 weeks. Another type of antibody emerges at around 16 weeks after infection and reaches its highest levels at 5 months of persistent virus presence. Researchers suggest that the presence of anti-TTV antibodies in the blood can be a sign of past infection.
Researchers in Belarus studied the detection rate of TTV, TTMDV, and TTMV in patients with chronic liver diseases and those without any signs of liver problems or viral hepatitis. The methods used to detect TTV DNA greatly influence its identification. Factors like the type of sample tested (such as plasma or whole blood) and the specific PCR assays or primers used can affect the detection of TTV DNA. Different studies have shown varying prevalence rates based on the detection methods used. Initially, scientists used specific primers to amplify a region called N22-ORF1 for diagnosing TTV infection. However, this region can vary a lot in the genetic material of the virus so using it for amplification might result in a lower detection rate for TTV. Instead, another region called UTR (untranslated region), which is more stable across different virus types, is now commonly used for detecting TTV infection.