Parasitic infection toxoplasmosis

Carbohydrate metabolism provides the main energy source in coccidia. Diets deficient in thiamin, riboflavin, or nicotinic acid—all cofactors in carbohydrate metabolism—result in suppression of parasitic infestation of chickens by E tenella and E acervulina. A thiamin analog, amprolium—1-[(4-amino-2-propyl-5-pyrimidinyl)-methyl]-2-picolinium chloride—has long been used as an effective anticoccidial agent in chickens and cattle with relatively low host toxicity. The antiparasitic activity of amprolium is reversible by thiamin and is recognized to involve inhibition of thiamin transport in the parasite. Unfortunately, amprolium has a rather narrow spectrum of antiparasitic activity it has poor activity against toxoplasmosis, a closely related parasitic infection. 

Toxoplasma gondii is the causative agent of toxoplasmosis, one of the most prevalent parasitic infections that afflict humans and other warm-blooded animals T. gondii is the only known species associated with toxoplasmosis (Tenter et al., 2000). It is estimated that approximately one-third of the human population worldwide have the parasite. 

Toxoplasmosis. This disease is caused by Toxoplasma gondii, which normally causes an asymptomatic infection in healthy adults. This protozoan also infects a very wide variety of animals domestic cats are one source of human infection. Unlike Cryptosporidium, Toxoplasma is an intracellular parasite and can invade numerous organs of infected individuals. In AIDS patients, the... 

The most widespread protozoan infections caused by pathogenic protozoa are malaria, leishmaniasis, and trypanosoma, as well as trichomonas, amebiasis, giardia, and toxoplasmosis. All types of protozoa are single-cell organisms that can adapt to various conditions. They are much more versatile than bacteria. They have a fairly complex life cycle, and therefore they exist in many forms. These forms require different approaches when treating patients that have protozoan infections. Protozoa are typical parasites that occupy host cells, multiply in them, and then destroy them. 

Toxoplasmosis is caused by infection with the protozoan parasite Toxoplasma gondii. In the immuno-... 

A. Liposomal amphotericin B was approved by the US. Food and Drug Administration to treat visceral leishmaniasis. Pentavalent antimony compounds, pentamidine, amphotericin B, and aminosi-dine (paromomycin) have all been demonstrated efficacious here. The liposomal amphotericin appears to be better taken up by the reticuloendothelial system, where the parasite resides, and partitions less in the kidney, where amphotericin B traditionally manifests its toxicity. In addition to being better tolerated by patients, it has proved to be very effective in India, where resistance to antimony drugs is widespread. This patient appears to have acquired his infection there, where many infected patients develop darkening of the skin, hence the name kala-azar, or black sickness. Albendazole, an anthelmintic, has no role here. Atovaquone, a naphthoquinone, is used to treat malaria, babesiosis, and pneumocystosis. Pyrimethamine-sulfadoxine is used to treat malaria and toxoplasmosis. Proguanil inhibits the dihydrofolate reductase of malaria parasites and is used in combination with atovaquone. 

Pyrimethamine may also be combined with other antimalarials such as artemisinin derivatives, but these regimens should only be used if the malarial parasites are not resistant to the specific drugs in the regimen.13 Pyrimethamine can also be combined with a sulfonamide drug such as dapsone, sulfadiazine, or sulfamethoxazole to treat protozoal infections that cause toxoplasmosis, or fungal infections that cause Pneumocystis pneumonia.These agents are administered orally. 

Toxoplasmosis is a recurrent, potentially blinding, disease caused by the obligate intracellular parasite Toxoplasma gondii. Toxoplasmosis affects millions of people worldwide. Cats are the definitive host for the parasite but not the primary source of human infection. Environmental contamination of the soil, water, fruits and vegetables, and infection in other animals cause most human infections. Human infection may be either congenital or acquired, and acquired disease appears to be the most prevalent. 

The esters also react readily with aryl hydrazines to give aryl hydrazone derivatives. Examples of the latter were first synthesized (prior to the availability of tetraalkyl carbonylphosphonates) from tetraalkyl methylenebisphosphonates and aryl diazonium salts, analogously to the phosphonoglyoxylate hydrazone synthesis described in a previous section. First made as possible precursors in a ketone synthesis, several of these compounds, converted to free acid salts by treatment with BTMS followed by dicyclohexylamine in methanol, proved to have unexpected inhibitory activity vs the pyrophosphate-dependent phospho-fructokinase of the parasite T. gondii, which causes a potentially lethal opportunistic infection in immunocompromised persons such as AIDS patients [94]. In fact, the 2,4-dinitrophenylhydrazone of carbonylbisphosphonic acid (as the tetrasodium salt) dramatically abated toxoplasmosis lesions in infected human foreskin fibroblasts [94]. Animal toxicity in this compound, probably arising from in vivo hydrolysis to the highly toxic hydrazine, precluded its future development, but the result remains an interesting lead. 

Protozoa usually can be identified in tissue sections stained with hematoxylin and eosin or Giemsa stain however, because of the small size of the organisms and the subtle distinguishing features, an unequivocal diagnosis cannot always be made. The role of IHC in the detection of protozoal infections has been particularly valuable in cases in which the morphology of the parasite is distorted by tissue necrosis or autolysis. In addition, in immunocompromised patients, toxoplasmosis can have an unusual disseminated presentation with numerous tachyzoites without bradyzoites (Fig. 

Generally, the diagnosis of toxoplasmosis in man may be done by serologic tests, PCR (which involves the amplification of specific nucleic acid sequences), histologic demonstration of the parasite, or by isolation of the protozoan that might be done by an animal infectivity assay or inoculation in human tissue cell cultures (Montoya, 2002). 

While prenatal diagnosis is based on the detection of T. gondii in the amniotic fluid, neonatal screening is based on the detection of parasites in the placenta and on the detection of IgM and IgA antibodies in newborns. PCR for the detection of parasite DNA in amniotic fluid has improved the sensitivity of prenatal diagnosis (Bessieres et ah, 2009). The accurate diagnosis of congenital toxoplasmosis is essential, since if the mother is treated it would reduce the probability of fetal infection by 50% (Desmonts and Couvreur, 1974). 

One-third of the human world population is infected with the protozoan parasite T. gondii. Recent calculations of the disease burden of toxoplasmosis rank this foodborne disease at the same level as salmonellosis or campylobacteriosis (Kijlstra and Jongert, 2008a). 

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