Neonatal sepsis of the newborn is an infection that has spread through the entire body. The inflammatory response to this systematic infection can be as serious as the infection itself. In infants that weigh under 1500 g, sepsis is the most common cause of death. Three to four percent of infants per 1000 births contract sepsis. The mortality rate from sepsis is near 25%. Infected sepsis in an infant can be identified by culturing the blood and spinal fluid and if suspected, intravenous antibiotics are usually started. Lumbar puncture is controversial because in some cases it has found not to be necessary while concurrently, without it estimates of missing up to one third of infants with meningitis is predicted.

Symptoms and the isolation of the virus pathogen the upper respiratory tract is diagnostic. Virus identification is specific immunologic methods and PCR. The presence of the virus can be rapidly confirmed by the detection of the virus antigen. The methods and materials used for identifying the RSV virus has a specificity and sensitivity approaching 85% to 95%. Not all studies confirm this sensitivity. Antigen detection has comparatively lower sensitivity rates that approach 65% to 75%.

Isolation is the implementation of isolating precautions designed to prevent transmission of microorganisms by common routes in hospitals. (See Universal precautions and Transmission-based precautions.) Because agent and host factors are more difficult to control, interruption of transfer of microorganisms is directed primarily at transmission for example isolation of infectious cases in special hospitals and isolation of patient with infected wounds in special rooms also isolation of joint transplantation patients on specific rooms.

Opportunistic infections caused by Feline Leukemia Virus and Feline immunodeficiency virus retroviral infections can be treated with Lymphocyte T-Cell Immune Modulator.

In addition to hand washing, gloves play an important role in reducing the risks of transmission of microorganisms. Gloves are worn for three important reasons in hospitals. First, they are worn to provide a protective barrier for personnel, preventing large scale contamination of the hands when touching blood, body fluids, secretions, excretions, mucous membranes, and non-intact skin. In the United States, the Occupational Safety and Health Administration has mandated wearing gloves to reduce the risk of bloodborne pathogen infections. Second, gloves are worn to reduce the likelihood that microorganisms present on the hands of personnel will be transmitted to patients during invasive or other patient-care procedures that involve touching a patient's mucous membranes and nonintact skin. Third, they are worn to reduce the likelihood that the hands of personnel contaminated with micro-organisms from a patient or a fomite can transmit those micro-organisms to another patient. In this situation, gloves must be changed between patient contacts, and hands should be washed after gloves are removed.

Wearing gloves does not replace the need for handwashing, because gloves may have small, undtectable defects or may be torn during use, and hands can become contaminated during removal of gloves. Failure to change gloves between patient contacts is an infection control hazard.

Individuals at higher risk are often prescribed prophylactic medication to prevent an infection from occurring. A patient's risk level for developing an opportunistic infection is approximated using the patient's CD4 T-cell count and sometimes other markers of susceptibility. Common prophylaxis treatments include the following:

People infected with CMV develop antibodies to it, initially IgM later IgG indicating current infection and immunity respectively. If the virus is detected in the blood, saliva, urine or other body tissues, it means that the person has an active infection.

When infected with CMV, most women have no symptoms, but some may have symptoms resembling mononucleosis. Women who develop a mononucleosis-like illness during pregnancy should consult their medical provider.

The Centers for Disease Control and Prevention (CDC) does not recommend routine maternal screening for CMV infection during pregnancy because there is no test that can definitively rule out primary CMV infection during pregnancy. Women who are concerned about CMV infection during pregnancy should practice CMV prevention measures.Considering that the CMV virus is present in saliva, urine, tears, blood, mucus, and other bodily fluids, frequent hand washing with soap and water is important after contact with diapers or oral secretions, especially with a child who is in daycare or interacting with other young children on a regular basis.

A diagnosis of congenital CMV infection can be made if the virus is found in an infant's urine, saliva, blood, or other body tissues during the first week after birth. Antibody tests cannot be used to diagnose congenital CMV; a diagnosis can only be made if the virus is detected during the first week of life. Congenital CMV cannot be diagnosed if the infant is tested more than one week after birth.

Visually healthy infants are not routinely tested for CMV infection although only 10–20% will show signs of infection at birth though up to 80% may go onto show signs of prenatal infection in later life. If a pregnant woman finds out that she has become infected with CMV for the first time during her pregnancy, she should have her infant tested for CMV as soon as possible after birth.

When physical examination of the newborn shows signs of a vertically transmitted infection, the examiner may test blood, urine, and spinal fluid for evidence of the infections listed above. Diagnosis can be confirmed by culture of one of the specific pathogens or by increased levels of IgM against the pathogen.

Use of male condoms or female condoms may help prevent the spread of trichomoniasis, although careful studies have never been done that focus on how to prevent this infection. Infection with Trichomoniasis through water is unlikely because "Trichomonas vaginalis" dies in water after 45–60 minutes, in thermal water after 30 minutes to 3 hours and in d urine after 5–6 hours.

Currently there are no routine standard screening requirements for the general U.S. population receiving family planning or STI testing. The Centers for Disease Control and Prevention (CDC) recommends Trichomoniasis testing for females with vaginal discharge and can be considered for females at higher risk for infection or of HIV-positive serostatus.

The advent of new, highly specific and sensitive trichomoniasis tests present opportunities for new screening protocols for both men and women. Careful planning, discussion, and research are required to determine the cost-efficiency and most beneficial use of these new tests for the diagnosis and treatment of trichomoniasis in the U.S., which can lead to better prevention efforts.

A number of strategies have been found to improve follow-up for STI testing including email and text messaging as reminders of appointments.

In a normal umbilical stump, you first see the umbilicus lose its characteristic bluish-white, moist appearance and become dry and black After several days to weeks, the stump should fall off and leave a pink fleshy wound which continues to heal as it becomes a normal umbilicus.

For an infected umbilical stump, diagnosis is usually made by the clinical appearance of the umbilical cord stump and the findings on history and physical examination. There may be some confusion, however, if a well-appearing neonate simply has some redness around the umbilical stump. In fact, a mild degree is common, as is some bleeding at the stump site with detachment of the umbilical cord. The picture may be clouded even further if caustic agents have been used to clean the stump or if silver nitrate has been used to cauterize granulomata of the umbilical stump.

The CDC states that PCR testing from a single blood draw is not sufficiently sensitive for "B." "henselae" testing, and can result in high false negative rates due to a small sample volume and levels below the limit of molecular detection.

"Bartonella" spp. are fastidious, slow-growing bacteria that are difficult to grow using traditional solid agar plate culture methods due to complex nutritional requirements and potentially a low number of circulating bacteria. This conventional method of culturing "Bartonella" spp. from blood inoculates plated directly onto solid agar plates requires an extended incubation period of 21 days due to the slow growth rate.

Diagnosis can be achieved through blood cultures, or cultures of other bodily fluids such as sputum. Bone marrow culture can often yield an earlier diagnosis, but is usually avoided as an initial diagnostic step because of its invasiveness.

Many people will have anemia and neutropenia if bone marrow is involved. MAC bacteria should always be considered in a person with HIV infection presenting with diarrhea.

The diagnosis requires consistent symptoms with two additional signs:

- Chest X-ray or CT scan showing evidence of right middle lobe (or left lingular lobe) lung infection

- Sputum culture or bronchoalveolar lavage culture demonstrating the infection is caused by MAC

Disseminated MAC is most readily diagnosed by one positive blood culture. Blood cultures should be performed in patients with symptoms, signs, or laboratory abnormalities compatible with mycobacterium infection. Blood cultures are not routinely recommended for asymptomatic persons, even for those who have CD4+ T-lymphocyte counts less than 100 cells/uL.

"Bartonella" growth rates improve when cultured in an enrichment inoculation step in a liquid insect-based medium such as "Bartonella" α-Proteobacteria Growth Medium (BAPGM) or Schneider’s Drosophila-based insect powder medium. Several studies have optimized the growing conditions of "Bartonella" spp. cultures in these liquid media, with no change in bacterial protein expressions or host interactions "in vitro". Insect-based liquid media supports the growth and co-culturing of at least seven "Bartonella" species, reduces bacterial culturing time and facilitates PCR detection and isolation of "Bartonella" spp. from animal and patient samples. Research shows that DNA may be detected following direct extraction from blood samples and become negative following enrichment culture, thus PCR is recommended after direct sample extraction and also following incubation in enrichment culture. Several studies have successfully optimized sensitivity and specificity by using PCR amplification (pre-enrichment PCR) and enrichment culturing of blood draw samples, followed by PCR (post-enrichment PCR) and DNA sequence identification.

Diagnosis of FVR is usually by clinical signs, especially corneal ulceration. Definitive diagnosis can be done by direct immunofluorescence or virus isolation. However, many healthy cats are subclinical carriers of feline herpes virus, so a positive test for FHV-1 does not necessarily indicate that signs of an upper respiratory tract infection are due to FVR. Early in the course of the disease, histological analysis of cells from the tonsils, nasal tissue, or nictitating membrane (third eyelid) may show inclusion bodies (a collection of viral particles) within the nucleus of infected cells.

During the 1950s there were outbreaks of omphalitis that then led to anti-bacterial treatment of the umbilical cord stump as the new standard of care. It was later determined that in developed countries keeping the cord dry is sufficient, (known as "dry cord care") as recommended by the American Academy of Pediatrics. The umbilical cord dries more quickly and separates more readily when exposed to air However, each hospital/birthing center has its own recommendations for care of the umbilical cord after delivery. Some recommend not using any medicinal washes on the cord. Other popular recommendations include triple dye, betadine, bacitracin, or silver sulfadiazine. With regards to the medicinal treatments, there is little data to support any one treatment (or lack thereof) over another. However one recent review of many studies supported the use of chlorhexidine treatment as a way to reduce risk of death by 23% and risk of omphalitis by anywhere between 27-56% in community settings in underdeveloped countries. This study also found that this treatment increased the time that it would take for the umbilical stump to separate or fall off by 1.7 days. Lastly this large review also supported the notion that in hospital settings no medicinal type of cord care treatment was better at reducing infections compared to dry cord care.

There are three main ways to test for Trichomoniasis.

- The first is known as saline microscopy. This is the most commonly used method and requires an endocervical, vaginal, or penile swab specimen for examination under a microscope. The presence of one or multiple trichomonads constitutes a positive result. This method is cheap but has a low sensitivity (60-70%) often due to an inadequate sample, resulting in false negatives.

- The second diagnostic method is culture, which has historically been the "gold standard" in infectious disease diagnosis. Trichomonas Vaginalis culture tests are relatively cheap; however, sensitivity is still somewhat low (70-89%).

- The third method includes the nucleic acid amplification tests (NAATs) which are more sensitive. These tests are more costly than microscopy and culture, and are highly sensitive (80-90%).

Most healthy people working with infants and children face no special risk from CMV infection. However, for women of child-bearing age who previously have not been infected with CMV, there is a potential risk to the developing unborn child (the risk is described above in the Pregnancy section). Contact with children who are in day care, where CMV infection is commonly transmitted among young children (particularly toddlers), may be a source of exposure to CMV. Since CMV is transmitted through contact with infected body fluids, including urine and saliva, child care providers (meaning day care workers, special education teachers, as well as mothers) should be educated about the risks of CMV infection and the precautions they can take. Day care workers appear to be at a greater risk than hospital and other health care providers, and this may be due in part to the increased emphasis on personal hygiene in the health care setting.

Recommendations for individuals providing care for infants and children:

- Employees should be educated concerning CMV, its transmission, and hygienic practices, such as handwashing, which minimize the risk of infection.

- Susceptible nonpregnant women working with infants and children should not routinely be transferred to other work situations.

- Pregnant women working with infants and children should be informed of the risk of acquiring CMV infection and the possible effects on the unborn child.

- Routine laboratory testing for CMV antibody in female workers is not specifically recommended due to its high occurrence, but can be performed to determine their immune status.

The following diagnostic methods are not routinely available to patients. Researchers have reported that they are more reliable at detecting infection, and in some cases can provide the physician with information to help determine whether "Blastocystis" infection is the cause of the patient's symptoms:

Serum antibody testing: A 1993 research study performed by the NIH with United States patients suggested that it was possible to distinguish symptomatic and asymptomatic infection with "Blastocystis" using serum antibody testing. The study used blood samples to measure the patient's immune reaction to chemicals present on the surface of the "Blastocystis" cell. It found that patients diagnosed with symptomatic "Blastocystis" infection exhibited a much higher immune response than controls who had "Blastocystis" infection but no symptoms. The study was repeated in 2003 at Ain Shams University in Egypt with Egyptian patients with equivalent results.

Fecal antibody testing: A 2003 study at Ain Shams University in Egypt indicated that patients symptomatically infected could be distinguished with a fecal antibody test. The study compared patients diagnosed with symptomatic "Blastocystis" infection to controls who had "Blastocystis" infection but no symptoms. In the group with symptoms, IgA antibodies to "Blastocystis" were detected in fecal specimens that were not present in the healthy control group.

Stool culture: Culturing has been shown to be a more reliable method of identifying infection. In 2006, researchers reported the ability to distinguish between disease causing and non-disease causing isolates of "Blastocystis" using stool culture. "Blastocystis" cultured from patients who were sick and diagnosed with "Blastocystis" infection produced large, highly adhesive amoeboid forms in culture. These cells were absent in "Blastocystis" cultures from healthy controls. Subsequent genetic analysis showed the "Blastocystis" from healthy controls was genetically distinct from that found in patients with symptoms. Protozoal culture is unavailable in most countries due to the cost and lack of trained staff able to perform protozoal culture.

Genetic analysis of isolates: Researchers have used techniques which allow the DNA of "Blastocystis" to be isolated from fecal specimens. This method has been reported to be more reliable at detecting "Blastocystis" in symptomatic patients than stool culture. This method also allows the species group of "Blastocystis" to be identified. Research is continuing into which species groups are associated with symptomatic (see Genetics and Symptoms) blastocystosis.

Immuno-fluorescence (IFA) stain: An IFA stain causes "Blastocystis" cells to glow when viewed under a microscope, making the diagnostic method more reliable. IFA stains are in use for Giardia and Cryptosporidium for both diagnostic purposes and water quality testing. A 1991 paper from the NIH described the laboratory development of one such stain. However, no company currently offers this stain commercially.

For sexually active women who are not pregnant, screening is recommended in those under 25 and others at risk of infection. Risk factors include a history of chlamydial or other sexually transmitted infection, new or multiple sexual partners, and inconsistent condom use. For pregnant women, guidelines vary: screening women with age or other risk factors is recommended by the U.S. Preventive Services Task Force (USPSTF) (which recommends screening women under 25) and the American Academy of Family Physicians (which recommends screening women aged 25 or younger). The American College of Obstetricians and Gynecologists recommends screening all at risk, while the Centers for Disease Control and Prevention recommend universal screening of pregnant women. The USPSTF acknowledges that in some communities there may be other risk factors for infection, such as ethnicity. Evidence-based recommendations for screening initiation, intervals and termination are currently not possible. For men, the USPSTF concludes evidence is currently insufficient to determine if regular screening of men for chlamydia is beneficial. They recommend regular screening of men who are at increased risk for HIV or syphilis infection.

In the United Kingdom the National Health Service (NHS) aims to:

1. Prevent and control chlamydia infection through early detection and treatment of asymptomatic infection;

2. Reduce onward transmission to sexual partners;

3. Prevent the consequences of untreated infection;

4. Test at least 25 percent of the sexually active under 25 population annually.

5. Retest after treatment.

Each type of vertically transmitted infection has a different prognosis. The stage of the pregnancy at the time of infection also can change the effect on the newborn.

Antigen ELISA and rtPCR are currently the most frequently performed tests to detect virus or viral antigen. Individual testing of ear tissue tag samples or serum samples is performed. It is vital that repeat testing is performed on positive samples to distinguish between acute, transiently infected cattle and PIs. A second positive result, acquired at least three weeks after the primary result, indicates a PI animal. rtPCR can also be used on bulk tank milk (BTM) samples to detect any PI cows contributing to the tank. It is reported that the maximum number of contributing cows from which a PI can be detected is 300.

Various diagnostic tests are available for the detection of either active infection or evidence of historical infection. The method of diagnosis used also depends upon whether the vet is investigating at an individual or a herd level.

Diagnosis is performed by determining if the infection is present, and then making a decision as to whether the infection is responsible for the symptoms. Diagnostic methods in clinical use have been reported to be of poor quality and more reliable methods have been reported in research papers.

For identification of infection, the only method clinically available in most areas is the "Ova and Parasite" (O&P) exam, which identifies the presence of the organism by microscopic examination of a chemically preserved stool specimen. This method is sometimes called "Direct Microscopy". In the United States, pathologists are required to report the presence of "Blastocystis" when found during an O&P exam, so a special test does not have to be ordered. Direct Microscopy is inexpensive, as the same test can identify a variety of gastrointestinal infections, such as "Giardia", "Entamoeba histolytica", "Cryptosporidium". However one laboratory director noted that pathologists using conventional microscopes failed to identify many "Blastocystis" infections, and indicated the necessity for special microscopic equipment for identification. The following table shows the sensitivity of Direct Microscopy in detecting "Blastocystis" when compared to stool culture, a more sensitive technique. Stool culture was considered by some researchers to be the most reliable technique, but a recent study found stool culture only detected 83% of individuals infected when compared to polymerase chain reaction (PCR) testing.

Reasons given for the failure of Direct Microscopy include: (1) Variable Shedding: The quantity of "Blastocystis" organisms varies substantially from day to day in infected humans and animals; (2) Appearance: Some forms of "Blastocystis" resemble fat cells or white blood cells, making it difficult to distinguish the organism from other cells in the stool sample; (3) Large number of morphological forms: "Blastocystis" cells can assume a variety of shapes, some have been described in detail only recently, so it is possible that additional forms exist but have not been identified.

Several methods have been cited in literature for determination of the significance of the finding of "Blastocystis":

1. Diagnosis only when large numbers of organism present: Some physicians consider "Blastocystis" infection to be a cause of illness only when large numbers are found in stool samples. Researchers have questioned this approach, noting that it is not used with any other protozoal infections, such as "Giardia" or "Entamoeba histolytica". Some researchers have reported no correlation between number of organisms present in stool samples and the level of symptoms. A study using polymerase chain reaction testing of stool samples suggested that symptomatic infection can exist even when sufficient quantities of the organism do not exist for identification through Direct Microscopy.

2. Diagnosis-by-exclusion: Some physicians diagnose "Blastocystis" infection by excluding all other causes, such as infection with other organisms, food intolerances, colon cancer, etc. This method can be time consuming and expensive, requiring many tests such as endoscopy and colonoscopy.

3. Disregarding "Blastocystis" : In the early to mid-1990s, some US physicians suggested all findings of "Blastocystis" are insignificant. No recent publications expressing this opinion could be found.

There is a vaccine for FHV-1 available (ATCvet code: , plus various combination vaccines), but although it limits or weakens the severity of the disease and may reduce viral shedding, it does not prevent infection with FVR. Studies have shown a duration of immunity of this vaccine to be at least three years. The use of serology to demonstrate circulating antibodies to FHV-1 has been shown to have a positive predictive value for indicating protection from this disease.

An individual may only develop signs of an infection after a period of subclinical infection, a duration that is called the incubation period. This is the case, for example, for subclinical sexually transmitted diseases such as AIDS and genital warts. Individuals with such subclinical infections, and those that never develop overt illness, creates a reserve of individuals that can transmit an infectious agent to infect other individuals. Because such cases of infections do not come to clinical attention, health statistics can often fail to measure the true prevalence of an infection in a population, and this prevents the accurate modeling of its infectious transmission.