Parasitology Notes
What are Nematodes? The word nematode is derived from Greek words- Nema meaning “thread” and oids meaning “resembling or forms”. Nematodes are also known by different names such as threadworms, roundworms, eelworms, and nema. Nematodes constitute the largest group of an animal kingdom comprising 80-90% of all multicellular animals. These … Read more
Strongyloides stercoralis is a parasitic roundworm that causes strongyloidiasis. It is commonly called a threadworm in the US. It is the smallest nematode known to cause infection in humans. They are unique among nematode because it has both parasitic and free-living form. Image Source: The Australian Society for Parasitology and CDC. … Read more
Fasciola hepatica is also known as a common liver fluke or sheep liver fluke. It causes hepatic fibrosis in ruminants and humans known as Fascioliasis. History and distribution of Fasciola hepatica Fasciola hepatica was the first fluke or trematode that was discovered more than 600 years ago in 1379 by … Read more
Introduction Giardia duodenalis is also known as Giardia lamblia and Giardia intestinalis. It is a flagellated unicellular eukaryotic microorganism that colonizes and reproduces in the small intestine. It commonly causes a gastrointestinal condition known as Giardiasis. Classification of Giardia duodenalis There are five species of Giardia, out of that, G. … Read more
Parasitic adaptation of flatworms Adaption in parasites to survive in the environment of a body of the host is called parasitic adaptation. Mainly flat-worm are parasitic except Turbellaria, so they are adapted for parasitic nature. There are two types of parasitic adaptation to suit their parasitic mode of life. Morphological … Read more
Locomotory Organelles in Protozoa Protozoan shows different verities of locomotory organs, such as pseudopodia, pellicular contractile structure, flagella, cilia. 1. Pseudopodia Pseudopodia are false feet of some Sarcodina protozoans such as Amoeba. Pseudopodia are a temporary structure form by streaming of cytoplasm. It is comprised of ectoplasm and endoplasm both. Pseudopodia … Read more
Types of parasitism in protozoa Before discussing parasitism in protozoa we have to understand the parasite and parasitism. We know that parasites can be defined as organism exists on another organism, parasites are two types one is ectoparasites, living on external body organism and another is endo-parasites, living inside the … Read more
What is Visceral leishmaniasis (Kala-azar)? Visceral leishmaniasis is sometimes known as systemic leishmaniasis or kala-azar. Kala-azar also is known as black fever or Dumdum fever in Asia. It usually occurs 3 to 6 months after being bitten by a sandfly. It primarily infects the reticuloendothelial system. It damages internal organs, … Read more
What is Cysticercosis? Cysticercosis refers to the tissue infection caused by the metacestode, or larval stage, of Taenia solium. It is acquired by the accidental ingestion of T. solium eggs. It is endemic to many parts of the developing world, including Latin America, Asia, and sub-Saharan Africa. Cysticercosis is the … Read more
Lab diagnosis of Ascaris lumbricoides a. Detection of Parasite Adult Worm In the case of heavy infection, the adult worm is possible to find in stool or sputum of the patient by the naked eye. Barium meal may reveal the presence of an adult worm in the small intestine. A … Read more
What is Ancylostoma duodenale? Ancylostoma duodenale is the most dangerous parasitic roundworm, causing serious infection in humans. It is commonly known as Old World hookworm. It is common in the tropical, subtropical, and temperate region of Asia, Africa, Europe, the Pacific Islands, and the Southern States of America. Ancylostoma duodenale … Read more
What is Plasmodium vivax? Plasmodium vivax is the most common of the human infecting malaria fever parasites. It is an intracellular parasite in man. It lives in the red blood corpuscles and liver cells in man. While extracellular in mosquitoes, living in its alimentary canal and salivary glands. The life … Read more
Plasmodium vivax is a widely distributed protozoal parasite and a human pathogen that is responsible for human malaria. P vivax is not virulent as compared to Plasmodium falciparum. Plasmodium vivax can cause severe disease and death due to the enlargement of the spleen. They are transmitted through the female Anopheles … Read more
Image Source: Laboratory Diagnostic Assistance (DPDx), CDC. Life history and Development of Taenia solium 1. Copulation and fertilization The life cycle of Taenia solium is digenetic, involving two hosts. But the life cycle of tapeworm is simple and without a free larval stage. Fertilization is preceded by copulation, inserting cirrus … Read more
Nutrition in Taenia solium Tapeworm completely lacks alimentation in all stages of life-history. It is clear that tapeworms absorb nutrients from their hosts and that such movement of materials from the hosts into parasites is an essential element of host-parasite relationships. The soluble nutrients like glucose, amino acids, glycerol, etc., … Read more
Systematic position Phylum: Protozoa Subphylum: Sacromastigophora Superclass: Mastigophora Class: Zoomastigophora Order: Kinetoplastida Genus: Leishmania Species: donovani Discovery and Distribution The species of Leishmania donovani was reported simultaneously by Leishmania from London and Donovan from Mardas in (1903) hence the name Leishmania donovani. L. donovani causes a malaria-like fever-oriental disease in … Read more
Classification of Taenia solium Phylum Platyhelminthes Class Cestoda Subclass Eucestoda Order Taenioidea Genus Taenia Species solium Habits and Habitat of Taenia solium Taenia solium, also known as pork tapeworm, is found worldwide. Thus, its distribution is cosmopolitan. Its adults dwell in man’s small intestine as an internal parasite, i.e., endoparasitic, … Read more
Life cycle of Ascaris lumbricoides In the life cycle of Ascaris, there is no secondary host. The life cycle of Ascaris is monogenetic as it involves only one host i.e. Man. Figure: Life cycle of Ascaris lumbricoides. Image Source: CDC. 1. Egg in feces The sexually mature female produces as … Read more
Reproductive system of Ascaris lumbricoides Only sexual reproduction occurs in Ascaris. Sexes are separate i.e., dioecious in Ascaris and these roundworms also show distinct sexual dimorphism. Males are smaller than the females and they also have a curved tail with pre and post anal papillae, cloaca, and a pair of … Read more