Antiparasitics are a class of medications which are indicated for the treatment of parasitic diseases, such as those caused by helminths, [1] amoeba, [2] ectoparasites, parasitic fungi, [3] and protozoa, [1] among others. Antiparasitics target the parasitic agents of the infections by destroying them or inhibiting their growth; [4] they are usually effective against a limited number of parasites within a particular class. Antiparasitics are one of the antimicrobial drugs which include antibiotics that target bacteria, and antifungals that target fungi. They may be administered orally, intravenously or topically. [4] Overuse or misuse of antiparasitics can lead to the development of antimicrobial resistance.
Broad-spectrum antiparasitics, analogous to broad-spectrum antibiotics for bacteria, are antiparasitic drugs with efficacy in treating a wide range of parasitic infections caused by parasites from different classes.
Antiparasitics treat parasitic diseases, which impact an estimated 2 billion people. [1]
Antiparastics may be given via a variety of routes depending on the specific medication, including oral, topical, and intravenous. [4]
Resistance to antiparasitics has been a growing concern, especially in veterinary medicine. The Egg hatch assay can be used to determine whether a parasite causing an infection has become resistant to standard drug treatments. [10]
Early antiparasitics were ineffective, frequently toxic to patients, and difficult to administer due to the difficulty in distinguishing between the host and the parasite. [4]
Between 1975 and 1999 only 13 of 1,300 new drugs were antiparasitics, which raised concerns that insufficient incentives existed to drive development of new treatments for diseases that disproportionately target low-income countries. This led to new public sector and public-private partnerships (PPPs), including investment by the Bill and Melinda Gates Foundation. Between 2000 and 2005, twenty new antiparasitic agents were developed or in development. [11] Metal-containing compounds are the subject of another avenue of approach. [12]
In the last decades, triazolopyrimidines and their metal complexes have been looked at as an alternative drug to the existing commercial antimonials, searching for a decrease in side effects and the development of parasite drug resistance. [13]
Leishmaniasis is a wide array of clinical manifestations caused by protozoal parasites of the Trypanosomatida genus Leishmania. It is generally spread through the bite of phlebotomine sandflies, Phlebotomus and Lutzomyia, and occurs most frequently in the tropics and sub-tropics of Africa, Asia, the Americas, and southern Europe. The disease can present in three main ways: cutaneous, mucocutaneous, or visceral. The cutaneous form presents with skin ulcers, while the mucocutaneous form presents with ulcers of the skin, mouth, and nose. The visceral form starts with skin ulcers and later presents with fever, low red blood cell count, and enlarged spleen and liver.
A parasitic disease, also known as parasitosis, is an infectious disease caused by parasites. Parasites are organisms which derive sustenance from its host while causing it harm. The study of parasites and parasitic diseases is known as parasitology. Medical parasitology is concerned with three major groups of parasites: parasitic protozoa, helminths, and parasitic arthropods. Parasitic diseases are thus considered those diseases that are caused by pathogens belonging taxonomically to either the animal kingdom, or the protozoan kingdom.
Parasitology is the study of parasites, their hosts, and the relationship between them. As a biological discipline, the scope of parasitology is not determined by the organism or environment in question but by their way of life. This means it forms a synthesis of other disciplines, and draws on techniques from fields such as cell biology, bioinformatics, biochemistry, molecular biology, immunology, genetics, evolution and ecology.
Giardiasis is a parasitic disease caused by Giardia duodenalis. Infected individuals who experience symptoms may have diarrhea, abdominal pain, and weight loss. Less common symptoms include vomiting and blood in the stool. Symptoms usually begin one to three weeks after exposure and, without treatment, may last two to six weeks or longer.
Ascariasis is a disease caused by the parasitic roundworm Ascaris lumbricoides. Infections have no symptoms in more than 85% of cases, especially if the number of worms is small. Symptoms increase with the number of worms present and may include shortness of breath and fever at the beginning of the disease. These may be followed by symptoms of abdominal swelling, abdominal pain, and diarrhea. Children are most commonly affected, and in this age group the infection may also cause poor weight gain, malnutrition, and learning problems.
Praziquantel (PZQ), sold under the brandname Biltricide among others, is a medication used to treat a number of types of parasitic worm infections in mammals, birds, amphibians, reptiles, and fish. In humans specifically, it is used to treat schistosomiasis, clonorchiasis, opisthorchiasis, tapeworm infections, cysticercosis, echinococcosis, paragonimiasis, fasciolopsiasis, and fasciolosis. It should not be used for worm infections of the eye. It is taken by mouth.
Hymenolepiasis is infestation by one of two species of tapeworm: Hymenolepis nana or H. diminuta. Alternative names are dwarf tapeworm infection and rat tapeworm infection. The disease is a type of helminthiasis which is classified as a neglected tropical disease.
Ivermectin is an antiparasitic drug. After its discovery in 1975, its first uses were in veterinary medicine to prevent and treat heartworm and acariasis. Approved for human use in 1987, it is used to treat infestations including head lice, scabies, river blindness (onchocerciasis), strongyloidiasis, trichuriasis, ascariasis and lymphatic filariasis. It works through many mechanisms to kill the targeted parasites, and can be taken by mouth, or applied to the skin for external infestations. It belongs to the avermectin family of medications.
Dwarf tapeworm is a cosmopolitan species though most common in temperate zones, and is one of the most common cestodes infecting humans, especially children.
Fumagillin is a complex biomolecule and used as an antimicrobial agent. It was isolated in 1949 from the microbial organism Aspergillus fumigatus.
Parasitic worms, also known as helminths, are a polyphyletic group of large macroparasites; adults can generally be seen with the naked eye. Many are intestinal worms that are soil-transmitted and infect the gastrointestinal tract. Other parasitic worms such as schistosomes reside in blood vessels.
Antiprotozoal agents is a class of pharmaceuticals used in treatment of protozoan infection.
Miltefosine, sold under the trade name Impavido among others, is a medication mainly used to treat leishmaniasis and free-living amoeba infections such as Naegleria fowleri and Balamuthia mandrillaris. This includes the three forms of leishmaniasis: cutaneous, visceral and mucosal. It may be used with liposomal amphotericin B or paromomycin. It is taken by mouth.
Nitazoxanide, sold under the brand name Alinia among others, is a broad-spectrum antiparasitic and broad-spectrum antiviral medication that is used in medicine for the treatment of various helminthic, protozoal, and viral infections. It is indicated for the treatment of infection by Cryptosporidium parvum and Giardia lamblia in immunocompetent individuals and has been repurposed for the treatment of influenza. Nitazoxanide has also been shown to have in vitro antiparasitic activity and clinical treatment efficacy for infections caused by other protozoa and helminths; evidence as of 2014 suggested that it possesses efficacy in treating a number of viral infections as well.
In enzymology, a pyruvate synthase is an enzyme that catalyzes the interconversion of pyruvate and acetyl-CoA. It is also called pyruvate:ferredoxin oxidoreductase (PFOR).
Protozoan infections are parasitic diseases caused by organisms formerly classified in the kingdom Protozoa. These organisms are now classified in the supergroups Excavata, Amoebozoa, Harosa, and Archaeplastida. They are usually contracted by either an insect vector or by contact with an infected substance or surface.
Anthelmintics or antihelminthics are a group of antiparasitic drugs that expel parasitic worms (helminths) and other internal parasites from the body by either stunning or killing them and without causing significant damage to the host. They may also be called vermifuges or vermicides. Anthelmintics are used to treat people who are infected by helminths, a condition called helminthiasis. These drugs are also used to treat infected animals, particularly small ruminants such as goats and sheep.
Jean-François Rossignol is a French scientist, a medicinal chemist and a physician, born in France on September 5, 1943. He was educated at the University of Paris, later specializing in tropical medicine. He then pursued a career in academia and in the pharmaceutical industry discovering and developing new drugs for the treatment of parasitic diseases such as halofantrine in the treatment of multidrug resistant Falciparum malaria or albendazole and nitazoxanide for the treatment of intestinal protozoan and helminthic infections. In 1993, he co-created his own pharmaceutical company, Romark Laboratories, L.C., to develop his own invention nitazoxanide, the first of the thiazolides. At Romark, he is the Chairman of the Board of Directors of the company and its Chief Science Officer. Following the discovery of the antiviral activity of the thiazolides Rossignol went to Stanford University in California to study interferon stimulated gene pathways and chronic viral hepatitis under Prof. Emmet Keeffe and Prof. Jeffery Glenn. It was in the Glenn laboratory that the mechanism of antiviral activity of nitazoxanide against the hepatitis C virus was discovered.
Soil-transmitted helminthiasis is a type of worm infection (helminthiasis) caused by different species of roundworms. It is caused specifically by worms transmitted through soil contaminated with faecal matter and are known as soil-transmitted helminths. Three types of soil-transmitted helminthiasis can be distinguished: ascariasis, hookworm infection and whipworm infection. These three types of infection are therefore caused by the large roundworm A. lumbricoides, the hookworms Necator americanus or Ancylostoma duodenale and by the whipworm Trichuris trichiura.
GNF6702 is the name for a broad-spectrum antiprotozoal drug invented by researchers working at the Genomics Institute of the Novartis Research Foundation in 2013, with activity against leishmaniasis, Chagas disease and sleeping sickness. These three diseases are caused by related kinetoplastid parasites, which share similar biology. GNF6702 acts as allosteric proteasome inhibitor which was effective against infection with any of the three protozoal diseases in mice, while having little evident toxicity to mammalian cells.
Nitazoxanide [NTZ: 2-acetyloxy-N-(5-nitro-2-thiazolyl)benzamide] is a thiazolide antiparasitic agent with excellent activity against a wide variety of protozoa and helminths. ... Nitazoxanide (NTZ) is a main compound of a class of broad-spectrum anti-parasitic compounds named thiazolides. It is composed of a nitrothiazole-ring and a salicylic acid moiety which are linked together by an amide bond ... NTZ is generally well tolerated, and no significant adverse events have been noted in human trials [13]. ... In vitro, NTZ and tizoxanide function against a wide range of organisms, including the protozoal species Blastocystis hominis, C. parvum, Entamoeba histolytica, G. lamblia and Trichomonas vaginalis [13]