Tests Explained. Infectious Disease. A- Serology

Transcription

1 Tests Explained Infectious Disease Measles A- Serology Measles is a disease caused by a virus. Symptoms include fever, cough, runny nose, red eyes and a generalized rash. Measles is spread through respiration (contact with fluids from an infected person's nose and mouth, either directly or through aerosol transmission), and is highly contagious. 90% of people without immunity sharing a house with an infected person will contract it. The incubation period usually lasts for 4 12 days (during which there are, by definition, no symptoms). Infected people remain contagious from the appearance of the first symptoms until 3 5 days after the rash appears. 'German measles' is an unrelated condition caused by the rubella virus. We test for the presence of antibodies in the blood against this virus. Presence of antibodies indicates that the individual has immunity against measles. Mumps Mumps or epidemic parotitis is a viral disease of humans. Prior to the development of a vaccine, it was a common childhood disease worldwide, and is still a significant threat to health in the third world. Painful swelling of the salivary glands (classically the parotid gland) is the most typical presentation. Painful testicular swelling and rash may also occur. The symptoms are generally not severe in children. In teenage males and men, complications such as infertility or sub-fertility are more common, although still rare in absolute terms. The disease is generally self-limited, running its course before receding, with no specific treatment apart from controlling the symptoms with painkillers. We test for the presence of antibodies in the blood against this virus, presence of

2 antibodies indicates that the individual has immunity against mumps. Rubella It is a viral disease known as German measles because the disease was first described by German physicians in the mid-eighteenth century. This disease is often mild, and can last one to three days. Children recover more quickly than adults. Infection of the mother by Rubella virus during pregnancy can be serious. If the mother is infected within the first 20 weeks of pregnancy, the child may be born with congenital rubella syndrome (CRS), which comprises a range of serious incurable illnesses. The developing fetus may suffer blindness, heart defects, hearing defects, musculoskeletal defects and mental retardation. Spontaneous abortion occurs in up to 20% of cases. Acquired rubella, (i.e. not congenital) is transmitted via airborne droplet transmission from the upper respiratory tract of active cases. The virus may also be present in the urine, feces and on the skin. There is no carrier state: the reservoir exists entirely in active human cases. The disease has an incubation period of 2 to 3 weeks. In most people the virus is rapidly eliminated. However, it may persist for some months post partum in infants surviving CRS. These children are a significant source of infection to other infants and, more importantly, to pregnant female contacts. We test for the presence of antibodies against Rubella to confirm the existence of adequate protection against the rubella virus and to detect a recent or past infection. It is also used to identify those who have never been exposed to the virus or have not been vaccinated. This test is ordered on all pregnant women and those planning to become pregnant to verify that they have a sufficient amount (titer) of rubella antibodies to protect them from infection. VZV VZV is a DNA virus and is a member of the herpes virus group. Like other herpes viruses, VZV has the capacity to persist in the body after the primary (first) infection as a latent infection. VZV persists in sensory nerve ganglia. Primary infection with VZV results in chickenpox. Herpes zoster (shingles) is the result of reactivation of latent VZV infection. The virus is believed to have a short survival time in the environment. The onset of maternal varicella from 5 days before to 2 days after delivery may result in overwhelming infection of the neonate and a fatality rate as high as 30%. This severe disease is believed to result from fetal exposure to varicella virus without the benefit of passive maternal antibody. Infants born to mothers with onset of maternal varicella 5 days or more prior to delivery usually have a benign course, presumably due to passive transfer of maternal antibody across the placenta We test for the presence of antibodies against Varisella zoster virus to confirm the existence of adequate protection against the Varisella zoster virus and to detect a recent or past infection. It is also used to identify those who have never been exposed to the virus or have not been vaccinated. This test is ordered on all pregnant women and those

3 planning to become pregnant to verify that they have a sufficient amount (titer) of rubella antibodies to protect them from infection. Toxoplasma Toxoplasma is a parasitic disease caused by the protozoan Toxoplasma gondii. The parasite infects many animal species and is common among domestic cats. Animals are infected by eating infected meat, by ingestion of feces of a cat that has recently been infected, or by transmission from mother to fetus. Cats are a major reservoir of this infection. Up to one third of the world's population is estimated to carry a Toxoplasma infection. The number of serologically positive individuals in the United States was found to be 10.8%, with average infection among women of childbearing age (15 to 44 years) of 11%. During the first few weeks, the infection typically causes a mild flu-like illness or no illness. After that, the parasite rarely causes any symptoms in otherwise healthy adults. However, people with a weakened immune system, such as those infected with HIV or pregnant, may become seriously ill and it can occasionally be fatal. The parasite can cause encephalitis (inflammation of the brain), neurologic diseases and affect the heart, liver, and eyes. We test for the presence of antibodies in the blood against this protozoon. Cytomegalo Virus (CMV) It is a member of the herpes virus family and has the characteristic ability to remain latent within the body over long periods. CMV infections are frequently associated with salivary glands, though they may be found throughout the body. CMV infection can also be life threatening for patients who are immune compromised (e.g. patients with HIV, organ transplant recipients or neonates). CMV is found throughout all geographic locations and socioeconomic groups, and infects between 50% and 80% of adults in the United States as indicated by the presence of antibodies in much of the general population. Serological prevalence is age-dependent with higher prevalence at older age groups. CMV is also the virus most frequently transmitted to a developing fetus. CMV infection is more widespread in developing countries and in communities with lower socioeconomic status and represents the most significant viral cause of birth defects in industrialized countries. We test for the presence of antibodies in the blood against CMV.

4 Hepatitis Panel Although hepatitis A virus, hepatitis B virus, and hepatitis C virus have similar names (because they all cause liver inflammation), these are distinctly different viruses both genetically and clinically. Hepatitis A (formerly known as infectious hepatitis), is an acute infectious disease of the liver caused by hepatitis A virus, which is most commonly transmitted by the fecal-oral route via contaminated food or drinking water. Every year, approximately 10 million people worldwide are infected with the virus. The time between infection and the appearance of the symptoms, (the incubation period), is between two and six weeks and the average incubation period is 28 days. In developing countries, and in regions with poor hygiene standards, the incidence of infection with this virus is high and the illness is usually contracted in early childhood. hepatitis A infection causes no clinical signs and symptoms in over 90% of these children and since the infection confers lifelong immunity, the disease is of no special significance to the indigenous population. In Europe, the United States and other industrialized countries, on the other hand, the infection is contracted primarily by susceptible young adults; most of them are infected with the virus during trips to countries with a high incidence of the disease. Hepatitis A does not have a chronic stage and does not cause permanent liver damage. Following infection, the immune system makes antibodies against the hepatitis A virus that confer immunity against future infection. The disease can be prevented by vaccination and hepatitis A vaccine has been proved effective in controlling outbreaks worldwide. We test for the presence of antibodies in the blood against this virus; presence of antibodies indicates that the individual has immunity against hepatitis A virus. Hepatitis B is a viral disease primarily involving the liver, which may be transmitted by contact with infected blood or body fluids. Once infected with the virus, individuals may carry the virus and infect others through exposure to blood, bodily fluids, or at childbirth. Hepatitis B virus infection may either be acute (self-limiting) or chronic (longstanding). Persons with self-limiting infection clear the infection spontaneously within weeks to months. Children are less likely than adults to clear the infection. More than 95% of people who become infected as adults or older children will stage a full recovery and develop protective immunity to the virus. However, only 5% of newborns that acquire the infection from their mother at birth will clear the infection. This population has a 40% lifetime risk of death from cirrhosis or hepatocellular carcinoma. Of those infected between the age of one to six, 70% will clear the infection. A simple blood test is available to screen individuals for the presence of Hepatitis B surface antigen, core antibody and e antigen. If a woman is known to be Hepatitis B

5 positive, her child should receive special medication at the time of childbirth to prevent infection with the hepatitis B virus. Hepatitis C The hepatitis C virus species is classified into six genotypes. Infection with one genotype does not confer immunity against others, and concurrent infection with two strains is possible. Infection is transmitted by contact with infected blood or body fluids. In most of these cases, one of the strains removes the other from the host in a short time. This finding opens the door to replace strains non-responsive to medication with others easier to treat. Unlike hepatitis A and B, there is currently no vaccine to prevent hepatitis C infection. We test for the presence of antibodies in the blood against this virus. Human Immunodeficiency Virus (HIV) 1&2 Plus O Only certain body fluids blood, semen (cum), pre-seminal fluid (pre-cum), rectal fluids, vaginal fluids, and breast milk from a person who has HIV can transmit HIV. These fluids must come in contact with a mucous membrane or damaged tissue or be directly injected into the bloodstream (from a needle or syringe) for transmission to occur. Mucous membranes are found inside the rectum, vagina, penis, and mouth. In the United States, HIV is spread mainly by o Having anal or vaginal sex with someone who has HIV without using a condom or taking medicines to prevent or treat HIV. o Anal sex is the highest-risk sexual behavior. For the HIV-negative partner, receptive anal sex (bottoming) is riskier than insertive anal sex (topping). o Vaginal sex is the second-highest-risk sexual behavior. o Sharing needles or syringes, rinse water, or other equipment (works) used to prepare drugs for injection with someone who has HIV. HIV can live in a used needle up to 42 days depending on temperature and other factors. Less commonly, HIV may be spread o From mother to child during pregnancy, birth, or breastfeeding. Although the risk can be high if a mother is living with HIV and not taking medicine, recommendations to test all pregnant women for HIV and start HIV treatment immediately have lowered the number of babies who are born with HIV. o By being stuck with an HIV-contaminated needle or other sharp object. This is a risk mainly for health care workers. o In extremely rare cases, HIV has been transmitted by o Oral sex putting the mouth on the penis (fellatio), vagina (cunnilingus), or anus (rimming). In general, there s little to no risk of getting HIV from oral sex. But transmission of HIV, though extremely rare, is theoretically possible if an HIVpositive man ejaculates in his partner s mouth during oral sex. o Receiving blood transfusions, blood products, or organ/tissue transplants that are contaminated with HIV. This was more common in the early years of HIV, but now the risk is extremely small because of rigorous testing of the US blood supply and donated organs and tissues.

6 o Eating food that has been pre-chewed by an HIV-infected person. The contamination occurs when infected blood from a caregiver s mouth mixes with food while chewing. The only known cases are among infants. o Being bitten by a person with HIV. Each of the very small number of documented cases has involved severe trauma with extensive tissue damage and the presence of blood. There is no risk of transmission if the skin is not broken. o Contact between broken skin, wounds, or mucous membranes and HIV-infected blood or blood-contaminated body fluids. o Deep, open-mouth kissing if both partners have sores or bleeding gums and blood from the HIV-positive partner gets into the bloodstream of the HIV-negative partner. HIV is not spread through saliva. We test for the presence of antibodies in the blood against HIV 1, HIV2 and HIV O. ZIKA Virus B- Nucliec Acid Testing Many people infected with Zika virus won t have symptoms or will only have mild symptoms. The most common symptoms of Zika are o Fever o Rash o Joint pain o Conjunctivitis (red eyes) o Muscle pain o Headache Zika is usually mild with symptoms lasting for several days to a week. People usually don t get sick enough to go to the hospital, and they very rarely die of Zika. For this reason, many people might not realize they have been infected. Symptoms of Zika are similar to other viruses spread through mosquito bites, like dengue and chikungunya. Zika virus usually remains in the blood of an infected person for about a week. If you develop symptoms and you live in or have recently traveled to an area with Zika. Zika virus can be passed from a pregnant woman to her fetus. Infection during pregnancy can cause certain birth defects Zika primarily spreads through infected mosquitoes. You can also get Zika through sex. There is no vaccine to prevent or medicine to treat Zika.

7 Herpes Simplex Virus 1&2 (HSV) Herpes simplex viruses 1 and 2 (HSV-1 and HSV-2) are neurotropic and neuro-invasive viruses; they enter and hide in the human nervous system, accounting for their durability in the human body. HSV-1 is commonly associated with herpes outbreaks of the face known as cold sores or fever blisters, whereas HSV-2 is more often associated with genital herpes. An infection by a herpes simplex virus is marked by watery blisters in the skin or mucous membranes of the mouth, lips or genitals. Lesions heal with a scab characteristic of herpetic disease. However, the infection is persistent and symptoms may recur periodically as outbreaks of sores near the site of original infection. After the initial or primary infection, HSV becomes latent in the cell bodies of nerves in the area. Some infected people experience sporadic episodes of viral reactivation, followed by transportation of the virus via the nerve's axon to the skin where virus replication and shedding occurs. Herpes is contagious if the carrier is producing and shedding the virus. This is especially likely during an outbreak but possible at other times. There is no cure yet, but there are treatments which reduce the likelihood of viral shedding. We test for the presence of HSV-1 and HSV-2 DNA in muco-cutaneos legions. Chlamydia trachomatis. Nucleic Acid Testing (NAT) Chlamydia infection is one of the most common sexually transmitted infections worldwide it is estimated that about 2.3 million individuals in the United States are infected with Chlamydia. It is the most common bacterial STD in humans. C. trachomatis is naturally found living only inside human cells. Chlamydia can be transmitted during vaginal, anal or oral sex, and can be passed from an infected mother to her baby during vaginal childbirth. Between half and three-quarters of all women who have a chlamydia infection of the neck of the womb (cervicitis) have no symptoms and do not know that they are infected. In men, infection of the urethra (urethritis) is usually symptomatic, causing a white discharge from the penis with or without pain on urinating (dysuria). Occasionally, the condition spreads to the upper genital tract in women (causing pelvic inflammatory disease) or to the epididymis in men (causing epididymitis). If untreated, chlamydial infections can cause serious reproductive and other health problems with both short-term and long-term consequences. Chlamydia is easily treated with antibiotics. Chlamydia conjunctivitis or trachoma is a common cause of blindness worldwide. We test for the nucleic acid of the bacteria in a swab or body secretion.

8 Neisseria gonorrhea. Nucleic Acid Testing (NAT) Also known as Gonococci (plural), or Gonococcus (singular), is a species of Gramnegative kidney bean-shaped diplococci bacteria responsible for the sexually transmitted disease gonorrhoea. Symptoms of infection with N. gonorrhoeae differ depending on the site of infection. Infection of the genitals can result in a purulent (or pus-like) discharge from the genitals which may be foul smelling, inflammation, redness, swelling, dysuria and a burning sensation during urination. N. gonorrhoeae can also cause conjunctivitis, pharyngitis, proctitis or urethritis, prostatitis and orchitis. Conjunctivitis is common in neonates. Neonatal gonorrheal conjunctivitis is contracted when the infant is exposed to N. gonorrhea in the birth canal, and can result in corneal scarring or perforation. Infection of the genitals in females with N. gonorrhea can result in pelvic inflammatory disease if left untreated, which can result in infertility. Pelvic inflammatory disease results if N. gonorrhea travels into the pelvic peritoneum via the cervix, endometrium and fallopian tubes. We test for the nucleic acid of the bacteria in swab or body secretion. Trichomonas vaginalis (NAAT) Trich is a very common sexually transmitted disease (STD) that is caused by infection with a protozoan parasite called Trichomonas vaginalis. Although symptoms of the disease vary, most women and men who have the parasite cannot tell they are infected. Trichomoniasis is considered the most common curable STD. In the United States, an estimated 3.7 million people have the infection, but only about 30% develop any symptoms of trichomoniasis. Infection is more common in women than in men, and older women are more likely than younger women to have been infected. The parasite is passed from an infected person to an uninfected person during sex. In women, the most commonly infected part of the body is the lower genital tract (vulva, vagina, or urethra), and in men, the most commonly infected body part is the inside of the penis (urethra). During sex, the parasite is usually transmitted from a penis to a vagina or from a vagina to a penis, but it can also be passed from a vagina to another vagina. It is not common for the parasite to infect other body parts, like the hands, mouth, or anus. It is unclear why some people with the infection get symptoms while others do not, but it probably depends on factors like the person s age and overall health. Infected people without symptoms can still pass the infection on to others. About 70% of infected people do not have any signs or symptoms. When trichomoniasis does cause symptoms, they can range from mild irritation to severe inflammation. Some people with symptoms get them within 5 to 28 days after being infected, but others do not develop symptoms until much later. Symptoms can come and go.

9 Men with trichomoniasis may feel itching or irritation inside the penis, burning after urination or ejaculation, or some discharge from the penis. Women with trichomoniasis may notice itching, burning, redness or soreness of the genitals, discomfort with urination, or a thin discharge with an unusual smell that can be clear, white, yellowish, or greenish. Having trichomoniasis can make it feel unpleasant to have sex. Without treatment, the infection can last for months or even years. Pregnant women are more likely to have their babies too early (preterm delivery). Also, babies born to infected mothers are more likely to have an officially low birth weight (less than 5.5 pounds). We test for the nucleic acid of the protozoon in swab or body secretion. Candidiasis (yeast infection); Candida albicans, Candida glbrata, C. parasilosis, C. dubliniesis, and C. tropicalis Genital / vulvovaginal candidiasis (VVC) is also sometimes called a "yeast infection. It is a common infection that occurs when there is overgrowth of the yeast called Candida. Candida is always present in and on the body in small amounts. However, when an imbalance occurs, such as when the normal acidity of the vagina changes or when hormonal balance changes, Candida can multiply. When that happens, symptoms of candidiasis may appear. Nearly 75% of all adult women have had at least one "yeast infection" in their lifetime. On rare occasions, men can also get genital candidiasis. VVC occurs more frequently and more severely in people with weakened immune systems We test for the nucleic acid of the fungus in vaginal swab or Thin Prep PAP smear. Bacterial Vaginosis; Gardnerela vaginalis & Lactobacilus gasseri, L. crispatus, and L. jenseni. Bacterial Vaginosis (BV) is a polymicrobial clinical syndrome resulting from replacement of the normal hydrogen peroxide producing Lactobacillus sp. in the vagina with high concentrations of anaerobic bacteria (e.g. Lactobacilus gasseri and crispatus ), G. vaginalis, Ureaplasma, Mycoplasma, and numerous fastidious or uncultivated anaerobes. Some women experience transient vaginal microbial changes, whereas others experience them for longer intervals of time. Among women presenting for care, BV is the most prevalent cause of vaginal discharge or malodor; however, in a nationally representative survey, most women with BV were asymptomatic The cause of the microbial alteration that precipitates BV is not fully understood, and whether BV results from acquisition of a single sexually transmitted pathogen is not

10 known. Nonetheless, women with BV are at increased risk for the acquisition of some STDs (e.g., HIV, N. gonorrhoeae, C. trachomatis, and HSV- 2), complications after gynecologic surgery, complications of pregnancy, and recurrence of BV. BV also increases the risk for HIV transmission to male sex Although BV-associated bacteria can be found in the male genitalia, treatment of male sex partners has not been beneficial in preventing the recurrence of BV. We test for the nucleic acid of the Bacteria in swab or body secretion and any imbalance Mycoplasma genitaluim become recognized as a cause of male urethritis, responsible for approximately 15% 20% of nongonococcal urethritis (NGU) cases, 20% 25% of nonchlamydial NGU, and approximately 30% of persistent or recurrent urethritis. In most settings, it is more common than N. gonorrhoeae but less common than C. trachomatis. While M. genitalium is often the sole pathogen detected, coinfection with C. trachomatis is not uncommon in selected areas Although strong and consistent evidence has linked M. genitalium to urethritis in men, it remains unknown whether this infection can cause male infertility or other male anogenital tract disease syndromes. The organism has been detected in men with epididymitis in a limited number of cases,. M. genitalium can be found in the vagina, cervix, and endometrium and, like chlamydial and gonococcal infections, M. genitalium infections in women are commonly asymptomatic. M. genitalium can be detected in 10% 30% of women with clinical cervicitis, and most studies have found that this organism is more common among women with cervicitis than those without this syndrome). A few seroepidemologic studies have found that women with tubal factor infertility are more likely to have antibodies to M. genitalium than fertile women, suggesting that this organism might cause female infertility. However, more research is needed. On the basis of certain reports, M. genitalium was uncommonly identified in women who experience adverse pregnancy outcomes, but was associated with increased risk for preterm delivery in one U.S. and another Peruvian study We test for the nucleic acid of the Mycoplasma in swab or body secretion.