Haseeb Ullah

Toxoplasma: Its Life Cycle, Symptoms, and Prevention Life cycle   Definitive Host: Domestic cats and other felines.   Intermediate Hosts : Humans and other mammals. Cycle in Cats: 1. Cats ingest cysts (e.g., from raw meat like mice). 2. Cysts release bradyzoites in the small intestine. 3. Bradyzoites infect mucosal cells and differentiate into gametocytes. 4. Gametocytes fuse to form oocysts. 5. Oocysts are excreted in cat feces. Human Infection: 1. Ingestion of cysts via:     Undercooked meat     Accidental contact with cat feces 2. Cysts rupture in the small intestine, releasing forms that invade the gut wall. 3. Forms differentiate into tachyzoites (rapidly multiplying trophozoites). 4. Tachyzoites infect various tissues (e.g., brain, muscle). 5. Tachyzoites transform into bradyzoites, forming tissue cysts. Transmission:   Contaminated soil with cat feces ingested inadvertently.   Consumption of undercooked meat from animals grazing in contam

  Leishmania donovani: Life Cycle, Pathogenesis, Treatment Prevention and Diagnosis   Leishmania donovani: The Causative Agent of Kalaazar (Visceral Leishmaniasis) Lifecycle   Reservoir Hosts: Various mammals (e.g., dogs, foxes, rodents).   Vector: Female sandflies.    Require blood meals for egg maturation.    Ingest macrophages containing amastigotes when feeding on an infected host. Inside the Sandfly: 1. Amastigotes transform into promastigotes in the gut. 2. Promastigotes multiply and migrate to the pharynx and proboscis. 3. This process takes about 10 days. Transmission to Humans: 1. Sandfly bites human, injecting promastigotes. 2. Promastigotes are engulfed by macrophages. 3. Inside macrophages, promastigotes transform back into amastigotes. Within the Human Host: 1. Amastigotes evade destruction by preventing vacuolelysosome fusion. 2. Infect other macrophages and reticuloendothelial cells. Cycle Completion:   Another sandfly ingests

  Definition Toxoplasma gondii (T. gondii) is a parasitic protozoan that causes toxoplasmosis, a disease transmitted through the ingestion of cysts in uncooked meat or food contaminated by cat feces. Life cycle The life cycle of Toxoplasma gondii involves various hosts and environments. Cats, as definitive hosts, play a crucial role in completing the parasite's sexual cycle. Oocysts shed in the feces of infected animals can be ingested by other hosts. Once ingested, oocysts transform into tachyzoites, which spread to different tissues via the bloodstream. Toxoplasmosis, caused by T. gondii, can also be transmitted through various means such as ingestion of raw or undercooked meat, congenital transfer, blood transfusion, or tissue transplant. Pathogenesis & Epidemiology Toxoplasma gondii is primarily acquired through the ingestion of cysts present in uncooked meat or food contaminated with cat feces. Transplacental transmission from an infected mother to the fetus is also

    Leishmania donovani: The Causative Agent of Kalaazar (Visceral Leishmaniasis) Lifecycle Leishmania donovani's life cycle, relies on sandflies as vectors and various mammals, including dogs, foxes, and rodents, as reservoirs. Female sandflies, requiring blood meals for egg maturation, ingest macrophages containing amastigotes when feeding on an infected host Inside the sandfly, the amastigotes transform into promastigotes in the gut, multiply, and migrate to the pharynx and proboscis, ready to be transmitted during the next bite. This sandfly phase takes about 10 days. Upon biting a human, the sandfly injects promastigotes, which are engulfed by macrophages and transform back into amastigotes (Figure 1). Amastigotes evade destruction by preventing the fusion of the vacuole with lysosomes, leading to the infection of other macrophages and reticuloendothelial cells. The cycle completes when another sandfly ingests macrophages containing amastigotes.                  

  Malaria  is caused by a parasite that destroys red blood cells and is transmitted by female Anopheles mosquitoes , Usually, mosquito’s bites late in the evening or at night. The primary causative agent of malaria is the protozoan Plasmodium , which includes several species such as 1.        Plasmodium vivax 2.        P. malariae 3.        P. falciparum 4.        P. ovale 5.        P. knowlesi Life Cycle: 1. The Plasmodium parasite initially infects female Anopheles mosquitoes . 2. Infected mosquitoes then transmit saliva containing sporozoites into the human bloodstream during a bite. 3. Sporozoites travel to the liver, reproduce asexually, and emerge as merozoites. 4. Merozoites invade red blood cells (RBCs) and form trophozoites , initiating a cycle of asexual reproduction. 5. Trophozoites develop into merozoites , causing RBCs to burst and release more parasites. 6. Some trophozoites develop into gametocytes, which are ingested by non-infected mosq

  Amoebiasis is a disease caused by Entamoeba histolytica , leading to ulcers in the large intestine. Mode of Transmission: The disease spreads through the fecal-oral route , primarily via contaminated water, food, flies , or through contact with contaminated hands. Life Cycle: Entamoeba cysts are present in the environment and then enter the body through ingestion. 1. Cysts undergo nuclear duplication. 2. The nucleus quadruplicates . 3. Multiplication begins through division. 4. The fourth stage involves the transformation into trophozoites . 5. Trophozoites undergo binary division . 6. The pre-cyst stage precedes cyst formation . Symptoms: Symptoms typically manifest 1-4 weeks after infection, including: ·          Diarrhea ·          Presence of blood in stool ·          Abdominal cramps and pain Diagnosis: - Trophozoites observed in a Stool Examination . - Cysts are identifiable in Sting Test of Stool . Treatment: Common treatments inc