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Antibody detection can be useful to indicate schistosome infection in people who have traveled to areas where schistosomiasis is common and in whom eggs cannot be demonstrated in fecal or urine specimens. Test sensitivity and specificity vary widely among the many tests reported for the serologic diagnosis of schistosomiasis and are dependent on both the type of antigen preparations used (crude, purified, adult worm, egg, cercarial) and the test procedure.
At CDC, a combination of tests with purified adult worm antigens is used for antibody detection. All serum specimens are tested by FAST-ELISA using "S. mansoni" adult microsomal antigen (MAMA). A positive reaction (greater than 9 units/µl serum) indicates infection with "Schistosoma" species. Sensitivity for "S. mansoni" infection is 99 percent, 95 percent for "S. haematobium" infection, and less than 50 percent for "S. japonicum" infection. Specificity of this assay for detecting schistosome infection is 99 percent. Because test sensitivity with the FAST-ELISA is reduced for species other than "S. mansoni", immunoblots of the species appropriate to the patient's travel history are also tested to ensure detection of "S. haematobium" and "S. japonicum" infections. Immunoblots with adult worm microsomal antigens are species-specific and so a positive reaction indicates the infecting species. The presence of antibody is indicative only of schistosome infection at some time and cannot be correlated with clinical status, worm burden, egg production, or prognosis. Where a person has traveled can help determine what "Schistosoma" species to test for by immunoblot.
In 2005, a field evaluation of a novel handheld microscope was undertaken in Uganda for the diagnosis of intestinal schistosomiasis by a team led by Russell Stothard from the Natural History Museum of London, working with the Schistosomiasis Control Initiative, London.
Diagnosis of toxoplasmosis in humans is made by biological, serological, histological, or molecular methods, or by some combination of the above. Toxoplasmosis can be difficult to distinguish from primary central nervous system lymphoma. It mimics several other infectious diseases so clinical signs are non-specific and are not sufficiently characteristic for a definite diagnosis. As a result, the diagnosis is made by a trial of therapy (pyrimethamine, sulfadiazine, and folinic acid (USAN: leucovorin)), if the drugs produce no effect clinically and no improvement on repeat imaging.
"T. gondii" may also be detected in blood, amniotic fluid, or cerebrospinal fluid by using polymerase chain reaction. "T. gondii" may exist in a host as an inactive cyst that would likely evade detection.
Serological testing can detect "T. gondii" antibodies in blood serum, using methods including the Sabin–Feldman dye test (DT), the indirect hemagglutination assay, the indirect fluorescent antibody assay (IFA), the direct agglutination test, the latex agglutination test (LAT), the enzyme-linked immunosorbent assay (ELISA), and the immunosorbent agglutination assay test (IAAT).
The most commonly used tests to measure IgG antibody are the DT, the ELISA, the IFA, and the modified direct agglutination test. IgG antibodies usually appear within a week or two of infection, peak within one to two months, then decline at various rates. "Toxoplasma" IgG antibodies generally persist for life, and therefore may be present in the bloodstream as a result of either current or previous infection.
To some extent, acute toxoplasmosis infections can be differentiated from chronic infections using an IgG avidity test, which is a variation on the ELISA. In the first response to infection, toxoplasma-specific IgG has a low affinity for the toxoplasma antigen; in the following weeks and month, IgG affinity for the antigen increases. Based on the IgG avidity test, if the IgG in the infected individual has a high affinity, it means that the infection began three to five months before testing. This is particularly useful in congenital infection, where pregnancy status and gestational age at time of infection determines treatment.
In contrast to IgG, IgM antibodies can be used to detect acute infection, but generally not chronic infection. The IgM antibodies appear sooner after infection than the IgG antibodies and disappear faster than IgG antibodies after recovery. In most cases, "T. gondii"-specific IgM antibodies can first be detected approximately a week after acquiring primary infection, and decrease within one to six months; 25% of those infected are negative for "T. gondii"-specific IgM within seven months. However, IgM may be detectable months or years after infection, during the chronic phase, and false positives for acute infection are possible. The most commonly used tests for the measurement of IgM antibody are double-sandwich IgM-ELISA, the IFA test, and the immunosorbent agglutination assay (IgM-ISAGA). Commercial test kits often have low specificity, and the reported results are frequently misinterpreted.
Recommendations for the diagnosis of congenital toxoplasmosis include: prenatal diagnosis based on testing of amniotic fluid and ultrasound examinations; neonatal diagnosis based on molecular testing of placenta and cord blood and comparative mother-child serologic tests and a clinical examination at birth; and early childhood diagnosis based on neurologic and ophthalmologic examinations and a serologic survey during the first year of life. During pregnancy, serological testing is recommended at three week intervals.
Even though diagnosis of toxoplasmosis heavily relies on serological detection of specific anti-"Toxoplasma" immunoglobulin, serological testing has limitations. For example, it may fail to detect the active phase of "T. gondii" infection because the specific anti-"Toxoplasma" IgG or IgM may not be produced until after several weeks of infection. As a result, a pregnant woman might test negative during the active phase of "T. gondii" infection leading to undetected and therefore untreated congenital toxoplasmosis. Also, the test may not detect "T. gondii" infections in immunocompromised patients because the titers of specific anti-"Toxoplasma" IgG or IgM may not rise in this type of patient.
Many PCR-based techniques have been developed to diagnose toxoplasmosis using clinical specimens that include amniotic fluid, blood, cerebrospinal fluid, and tissue biopsy. The most sensitive PCR-based technique is nested PCR, followed by hybridization of PCR products. The major downside to these techniques is that they are time consuming and do not provide quantitative data.
Real-time PCR is useful in pathogen detection, gene expression and regulation, and allelic discrimination. This PCR technique utilizes the 5' nuclease activity of "Taq" DNA polymerase to cleave a nonextendible, fluorescence-labeled hybridization probe during the extension phase of PCR. A second fluorescent dye, e.g., 6-carboxy-tetramethyl-rhodamine, quenches the fluorescence of the intact probe. The nuclease cleavage of the hybridization probe during the PCR releases the effect of quenching resulting in an increase of fluorescence proportional to the amount of PCR product, which can be monitored by a sequence detector.
Toxoplasmosis cannot be detected with immunostaining. Lymph nodes affected by "Toxoplasma" have characteristic changes, including poorly demarcated reactive germinal centers, clusters of monocytoid B cells, and scattered epithelioid histiocytes.
The classic triad of congenital toxoplasmosis includes: chorioretinitis, hydrocephalus, and intracranial artheriosclerosis.
Diagnosis of infection is confirmed by the identification of eggs in stools. Eggs of "S. mansoni" are approximately 140 by 60 µm in size, and have a lateral spine. The diagnosis is improved by the use of the Kato-Katz technique (a semi-quantitative stool examination technique). Other methods that can be used are enzyme-linked immunosorbent assay (ELISA), circumoval precipitation test, and alkaline phosphatase immunoassay.
Microscopic identification of eggs in stool or urine is the most practical method for diagnosis. Stool examination should be performed when infection with "S. mansoni" or "S. japonicum" is suspected, and urine examination should be performed if "S. haematobium" is suspected. Eggs can be present in the stool in infections with all "Schistosoma" species. The examination can be performed on a simple smear (1 to 2 mg of fecal material). Since eggs may be passed intermittently or in small amounts, their detection will be enhanced by repeated examinations and/or concentration procedures. In addition, for field surveys and investigational purposes, the egg output can be quantified by using the Kato-Katz technique (20 to 50 mg of fecal material) or the Ritchie technique. Eggs can be found in the urine in infections with "S. haematobium" (recommended time for collection: between noon and 3 PM) and with "S. japonicum". Quantification is possible by using filtration through a nucleopore filter membrane of a standard volume of urine followed by egg counts on the membrane. Tissue biopsy (rectal biopsy for all species and biopsy of the bladder for "S. haematobium") may demonstrate eggs when stool or urine examinations are negative.
Only specialized laboratories can adequately diagnose "Babesia" infection in humans, so "Babesia" infections are considered highly under-reported. It develops in patients who live in or travel to an endemic area or receive a contaminated blood transfusion within the preceding 9 weeks, so this aspect of the medical history is vital. Babesiosis may be suspected when a person with such an exposure history develops persistent fevers and hemolytic anemia. The definitive diagnostic test is the identification of parasites on a Giemsa-stained thin-film blood smear.
So-called "Maltese cross formations" on the blood film are diagnostic (pathognomonic) of babesiosis, since they are not seen in malaria, the primary differential diagnosis. Careful examination of multiple smears may be necessary, since "Babesia" may infect less than 1% of circulating red blood cells, thus be easily overlooked.
Serologic testing for antibodies against "Babesia" (both IgG and IgM) can detect low-level infection in cases with a high clinical suspicion, but negative blood film examinations. Serology is also useful for differentiating babesiosis from malaria in cases where people are at risk for both infections. Since detectable antibody responses require about a week after infection to develop, serologic testing may be falsely negative early in the disease course.
A polymerase chain reaction (PCR) test has been developed for the detection of "Babesia" from the peripheral blood. PCR may be at least as sensitive and specific as blood-film examination in diagnosing babesiosis, though it is also significantly more expensive. Most often, PCR testing is used in conjunction with blood film examination and possibly serologic testing.
Other laboratory findings include decreased numbers of red blood cells and platelets on complete blood count.
In animals, babesiosis is suspected by observation of clinical signs (hemoglobinuria and anemia) in animals in endemic areas. Diagnosis is confirmed by observation of merozoites on thin film blood smear examined at maximum magnification under oil using Romonovski stains (methylene blue and eosin). This is a routine part of the veterinary examination of dogs and ruminants in regions where babesiosis is endemic.
"Babesia canis" and "B. bigemina" are "large "Babesia" species" that form paired merozoites in the erythrocytes, commonly described as resembling "two pears hanging together", rather than the "Maltese cross" of the "small "Babesia" species". Their merozoites are around twice the size of small ones.
Cerebral babesiosis is suspected "in vivo" when neurological signs (often severe) are seen in cattle that are positive for "B. bovis" on blood smear, but this has yet to be proven scientifically. Outspoken red discoloration of the grey matter "post mortem" further strengthens suspicion of cerebral babesiosis. Diagnosis is confirmed "post mortem" by observation of "Babesia"-infected erythrocytes sludged in the cerebral cortical capillaries in a brain smear.
A stool ova and parasites exam reveals the presence of typical whipworm eggs. Typically, the Kato-Katz thick-smear technique is used for identification of the "Trichuris trichiura" eggs in the stool sample.
Although colonoscopy is not typically used for diagnosis, as the adult worms can be overlooked, especially with imperfect colon, there have been reported cases in which colonoscopy has revealed adult worms. Colonoscopy can directly diagnose trichuriasis by identification of the threadlike form of worms with an attenuated, whip-like end. Colonoscopy has been shown to be a useful diagnostic tool, especially in patients infected with only a few male worms and with no eggs presenting in the stool sample.
Trichuriasis can be diagnosed when "T. trichiura" eggs are detected in stool examination. Eggs will appear barrel-shaped and unembryonated, having bipolar plugs and a smooth shell. Rectal prolapse can be diagnosed easily using defecating proctogram and is one of many methods for imaging the parasitic infection. Sigmoidoscopys show characteristic white bodies of adult worms hanging from inflamed mucosa ("coconut cake rectum").
Limited access to essential medicine poses a challenge to the eradication of trichuriasis worldwide. Also, it is a public health concern that rates of post-treatment re-infection need to be determined and addressed to diminish the incidence of untreated re-infection. Lastly, with mass drug administration strategies and improved diagnosis and prompt treatment, detection of an emergence of antihelminthic drug resistance should be examined.
Mass Drug Administration (preventative chemotherapy) has had a positive effect on the disease burden of trichuriasis in East and West Africa, especially among children, who are at highest risk for infection.
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.
Specific helminths can be identified through microscopic examination of their eggs (ova) found in faecal samples. The number of eggs is measured in units of eggs per gram. However, it does not quantify mixed infections, and in practice, is inaccurate for quantifying the eggs of schistosomes and soil-transmitted helmiths. Sophisticated tests such as serological assays, antigen tests, and molecular diagnosis are also available; however, they are time-consuming, expensive and not always reliable.
The most common medications used to treat coccidian infections are in the sulfonamide antibiotic family.
Depending on the pathogen and the condition of the animal, untreated coccidiosis may clear of its own accord, or become severe and damaging, and sometimes cause death.
One strategy for the prevention of infection transmission between cats and people is to better educate people on the behaviour that puts them at risk for becoming infected.
Those at the highest risk of contracting a disease from a cat are those with behaviors that include: being licked, sharing food, sharing kithchen utensils, kissing, and sleeping with a cat. The very young, the elderly and those who are immunocompromised increase their risk of becoming infected when sleeping with their cats (and dogs). The CDC recommends that cat owners not allow a cat to lick your face because it can result in disease transmission. If someone is licked on their face, mucous membranes or an open wound, the risk for infection is reduced if the area is immediately washed with soap and water. Maintaining the health of the animal by regular inspection for fleas and ticks, scheduling deworming medications along with veterinary exams will also reduce the risk of acquiring a feline zoonosis.
Recommendations for the prevention of ringworm transmission to people include:
- regularly vacuuming areas of the home that pets commonly visit helps to remove fur or flakes of skin
- washing the hands with soap and running water after playing with or petting your pet.
- wearing gloves and long sleeves when handling cats infected with.
- disinfect areas the pet has spent time in, including surfaces and bedding.
- the spores of this fungus can be killed with common disinfectants like chlorine bleach diluted 1:10 (1/4 cup in 1 gallon of water), benzalkonium chloride, or strong detergents.
- not handling cats with ringworm by those whose immune system is weak in any way (if you have HIV/AIDS, are undergoing cancer treatment, or are taking medications that suppress the immune system, for example).
- taking the cat to the veterinarian if ringworm infection is suspected.
Puppies are frequently infected with coccidia from the feces of their mother, and are more likely to develop coccidiosis due to their undeveloped immune systems. Stress can trigger symptoms in susceptible animals.
Symptoms in young dogs include diarrhea with mucus and blood, poor appetite, vomiting, and dehydration. Untreated the disease can be fatal.
Treatment is routine and effective. Diagnosis is made by low-powered microscopic examination of the feces, which is generally replete with oocysts. Readily available drugs eliminate the protozoa or reduce them enough that the animal's immune system can clear the infection. Permanent damage to the gastrointestinal system is rare, and a dog will usually suffer no long-lasting negative effects.
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.
Diagnosis is usually performed by submitting multiple stool samples for examination by a parasitologist in a procedure known as an ova and parasite examination. About 30% of children with "D. fragilis" infection exhibit peripheral blood eosinophilia.
A minimum of three stool specimens having been immediately fixed in polyvinyl alcohol fixative, sodium acetate-acetic acid-formalin fixative, or Schaudinn's fixative should be submitted, as the protozoan does not remain morphologically identifiable for long. All specimens, regardless of consistency, are permanently stained prior to microscopic examination with an oil immersion lens. The disease may remain cryptic due to the lack of a cyst stage if these recommendations are not followed.
The trophozoite forms have been recovered from formed stool, thus the need to perform the ova and parasite examination on specimens other than liquid or soft stools. DNA fragment analysis provides excellent sensitivity and specificity when compared to microscopy for the detection of "D. fragilis" and both methods should be employed in laboratories with PCR capability. The most sensitive detection method is parasite culture, and the culture medium requires the addition of rice starch.
An indirect fluorescent antibody (IFA) for fixed stool specimens has been developed.
1. One researcher investigated the phenomenon of symptomatic relapse following treatment of infection with "D. fragilis" in association with its apparent disappearance from stool samples. The organism could still be detected in patients through colonoscopy or by examining stool samples taken in conjunction with a saline laxative.
2. A study found that trichrome staining, a traditional method for identification, had a sensitivity of 36% (9/25) when compared to stool culture.
3. An additional study found that the sensitivity of staining was 50% (2/4), and that the organism could be successfully cultured in stool specimens up to 12-hours old that were kept at room temperature.
Diagnosis depends on finding characteristic worm eggs on microscopic examination of the stools, although this is not possible in early infection. Early signs of infection in most dogs include limbular limping and anal itching. The eggs are oval or elliptical, measuring 60 µm by 40 µm, colorless, not bile stained and with a thin transparent hyaline shell membrane. When released by the worm in the intestine, the egg contains an unsegmented ovum. During its passage down the intestine, the ovum develops and thus the eggs passed in feces have a segmented ovum, usually with 4 to 8 blastomeres.
As the eggs of both "Ancylostoma" and "Necator" (and most other hookworm species) are indistinguishable, to identify the genus, they must be cultured in the lab to allow larvae to hatch out. If the fecal sample is left for a day or more under tropical conditions, the larvae will have hatched out, so eggs might no longer be evident. In such a case, it is essential to distinguish hookworms from "Strongyloides" larvae, as infection with the latter has more serious implications and requires different management. The larvae of the two hookworm species can also be distinguished microscopically, although this would not be done routinely, but usually for research purposes. Adult worms are rarely seen (except via endoscopy, surgery or autopsy), but if found, would allow definitive identification of the species. Classification can be performed based on the length of the buccal cavity, the space between the oral opening and the esophagus: hookworm rhabditoform larvae have long buccal cavities whereas "Strongyloides" rhabditoform larvae have short buccal cavities.
Recent research has focused on the development of DNA-based tools for diagnosis of infection, specific identification of hookworm, and analysis of genetic variability within hookworm populations. Because hookworm eggs are often indistinguishable from other parasitic eggs, PCR assays could serve as a molecular approach for accurate diagnosis of hookworm in the feces.
In regions where helminthiasis is common, mass deworming treatments may be performed, particularly among school-age children, who are a high-risk group. Most of these initiatives are undertaken by the World Health Organization (WHO) with positive outcomes in many regions. Deworming programs can improve school attendance by 25 percent. Although deworming improves the health of an individual, outcomes from mass deworming campaigns, such as reduced deaths or increases in cognitive ability, nutritional benefits, physical growth, and performance, are uncertain or not apparent.
Evaluation of numerous public health interventions has generally shown that improvement in each individual component ordinarily attributed to poverty (for example, sanitation, health education and underlying nutrition status) often have minimal impact on transmission. For example, one study found that the introduction of latrines into a resource-limited community only reduced the prevalence of hookworm infection by four percent. However, another study in Salvador, Brazil found that improved drainage and sewerage had a significant impact (p<0.0001) on the prevalence of hookworm infection but no impact at all on the intensity of hookworm infection. This seems to suggest that environmental control alone has a limited but incomplete effect on the transmission of hookworms. It is imperative, therefore, that more research is performed to understand the efficacy and sustainability of integrated programs that combine numerous preventive methods including education, sanitation, and treatment.
Treatment of asymptomatic carriers should be considered if parasites are still detected after 3 months. In mild-to-moderate babesiosis, the treatment of choice is a combination of atovaquone and azithromycin. This regimen is preferred to clindamycin and quinine because side effects are fewer. The standard course is 7 to 10 days, but this is extended to at least 6 weeks in people with relapsing disease. Even mild cases are recommended to be treated to decrease the chance of inadvertently transmitting the infection by donating blood. In life-threatening cases, exchange transfusion is performed. In this procedure, the infected red blood cells are removed and replaced with uninfected ones.
Imizol is a drug used for treatment of babesiosis in dogs.
Extracts of the poisonous, bulbous plant "Boophone disticha" are used in the folk medicine of South Africa to treat equine babesiosis. "B. disticha" is a member of the daffodil family Amaryllidaceae and has also been used in preparations employed as arrow poisons, hallucinogens, and in embalming. The plant is rich in alkaloids, some of which display an action similar to that of scopolamine.
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.
Feline zoonosis are the viral, bacterial, fungal, protozoan, nematode and arthropod infections that can be transmitted to humans from the domesticated cat, "Felis catus". Some of these are diseases are reemerging and newly emerging infections or infestations caused by zoonotic pathogens transmitted by cats. In some instances, the cat can display symptoms of infection (these may differ from the symptoms in humans) and sometimes the cat remains asymptomatic. There can be serious illnesses and clinical manifestations in people who become infected. This is dependent on the immune status and age of the person. Those who live in close association with cats are more prone to these infections. But those that do not keep cats as pets are also able to acquire these infections because of the transmission can be from cat feces and the parasites that leave their bodies.
People can acquire cat-associated infections through bites, scratches or other direct contact of the skin or mucous membranes with the cat. This includes 'kissing' or letting the animal lick the mouth or nose. Mucous membranes are easily infected when the pathogen is in the mouth of the cat. Pathogens can also infect people when there is contact with animal saliva, urine and other body fluids or secretions, When fecal material is unintentionally ingested, infection can occur. Feline zooinosis can be acquired by a person by inhalation of aerosols or droplets coughed up by the cat.
In the United States, forty percent of homes have at least one cat. Some contagious infections such as campylobacteriosis and salmonellosis cause visible symptoms of the disease in cats. Other infections, such as cat scratch disease and toxoplasmosis, have no visible symptoms and are carried by apparently healthy cats.
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.
Antibody (Ig) ELISAs are used to detect historical BVDV infection; these tests have been validated in serum, milk and bulk milk samples. Ig ELISAs do not diagnose active infection but detect the presence of antibodies produced by the animal in response to viral infection. Vaccination also induces an antibody response, which can result in false positive results, therefore it is important to know the vaccination status of the herd or individual when interpreting results. A standard test to assess whether virus has been circulating recently is to perform an Ig ELISA on blood from 5–10 young stock that have not been vaccinated, aged between 9 and 18 months. A positive result indicates exposure to BVDV, but also that any positive animals are very unlikely to be PI animals themselves. A positive result in a pregnant female indicates that she has previously been either vaccinated or infected with BVDV and could possibly be carrying a PI fetus, so antigen testing of the newborn is vital to rule this out. A negative antibody result, at the discretion of the responsible veterinarian, may require further confirmation that the animal is not in fact a PI.
At a herd level, a positive Ig result suggests that BVD virus has been circulating or the herd is vaccinated. Negative results suggest that a PI is unlikely however this naïve herd is in danger of severe consequences should an infected animal be introduced. Antibodies from wild infection or vaccination persist for several years therefore Ig ELISA testing is more valuable when used as a surveillance tool in seronegative herds.
Concomitant pinworm infection should also be excluded, although the association has not been proven. Successful treatment of the infection with iodoquinol, doxycycline, metronidazole, paromomycin, and secnidazole has been reported. Resistance requires the use of combination therapy to eradicate the organism. All persons living in the same residence should be screened for "D. fragilis", as asymptomatic carriers may provide a source of repeated infection. Paromomycin is an effective prophylactic for travellers who will encounter poor sanitation and unsafe drinking water.
Biotechnology companies in the developing world have targeted neglected tropical diseases due to need to improve global health.
Mass drug administration is considered a possible method for eradication, especially for lymphatic filariasis, onchocerciasis, and trachoma, although drug resistance is a potential problem. According to Fenwick, Pfizer donated 70 million doses of drugs in 2011 to eliminate trachoma through the International Trachoma Initiative. Merck has helped The African Programme for the Control of Onchocerciasis (APOC) and Oncho Elimination Programme for the Americas to greatly diminished the effect of Onchocerciasis by donating ivermectin. Merck KGaA pledged to give 200 million tablets of praziquantel over 10 years, the only cure for schistosomiasis. GlaxoSmithKline has donated two billion tablets of medicine for lymphatic filariasis and pledged 400 million deworming tablets per year for five years in 2010. Johnson & Johnson has pledged 200 million deworming tablets per year. Novartis has pledged leprosy treatment, EISAI pledged two billion tablets to help treat lymphatic filariasis.
Although no specific treatment for acute infection with SuHV1 is available, vaccination can alleviate clinical signs in pigs of certain ages. Typically, mass vaccination of all pigs on the farm with a modified live virus vaccine is recommended. Intranasal vaccination of sows and neonatal piglets one to seven days old, followed by intramuscular (IM) vaccination of all other swine on the premises, helps reduce viral shedding and improve survival. The modified live virus replicates at the site of injection and in regional lymph nodes. Vaccine virus is shed in such low levels, mucous transmission to other animals is minimal. In gene-deleted vaccines, the thymidine kinase gene has also been deleted; thus, the virus cannot infect and replicate in neurons. Breeding herds are recommended to be vaccinated quarterly, and finisher pigs should be vaccinated after levels of maternal antibody decrease. Regular vaccination results in excellent control of the disease. Concurrent antibiotic therapy via feed and IM injection is recommended for controlling secondary bacterial pathogens.