clin para pt 1

• Toxoplasma gondii


  A protozoan parasite that infects most species of warm-blooded animals, including humans, and causes the disease toxoplasmosis
• Definitive hosts for Toxoplasma gondii

  Members of family Felidae

  
• In most cases, Toxoplasma gondii infection is asymptomatic, but devastating disease can occur

  
• Toxoplasma gondii cysts

  • Usually range in size from 5-50 µm in diameter
  • Usually spherical in the brain but more elongated in cardiac and skeletal muscles
  • May be found in various sites throughout the body of the host
  • Most common in the brain and skeletal and cardiac muscles

  
• Toxoplasma gondii trophozoites

  • Approximately 4-8 µm long by 2-3 µm wide
  • Tapered anterior end
  • Blunt posterior end
  • Large nucleus
  • May be found in various sites throughout the body of the host

  
• Toxoplasma gondii life cycle

  1. Infective stages include tachyzoite, bradyzoite, and oocyst

  2. Complete life cycle occurs only in members of the cat family (Felidae)

  3. Follows a typical coccidian life cycle consisting of schizogony, gametogony, and sporogony in the intestinal epithelium

  4. Extraintestinal stages are the asexual stages: tachyzoites and bradyzoites

  
• Toxoplasma gondii oocyst

  • Ovoidal in shape
  • Has a thin wall
  • Measures 10 to 13 µm by 9 to 11 µm

  
• Tachyzoites


  The replicating stage of the Toxoplasma gondii parasite
• Bradyzoites


  The more slowly replicating stage of the Toxoplasma gondii parasite
• Toxoplasma gondii infection process

  1. Ingested oocysts enter host cells either by rupturing the membrane or by invaginating them

  2. After multiplication by repeated endodyogeny, the macrophage finally ruptures, liberating the replicating tachyzoites

  3. Tachyzoites give rise to the formation of pseudocysts and cysts that contain the bradyzoites

  4. Cysts persist in latent form for the entire lifespan of the host, and can be reactivated in immunosuppressed persons
• The incidence of toxoplasmosis has raised dramatically with the increasing population of AIDS patients
• Forms of clinical manifestation of Toxoplasma gondii infection

  • Lymphadenitis
  • Encephalitis

  
• Most people infected with toxoplasmosis do not have any symptoms
• Toxoplasmosis is endemic worldwide in humans and in domestic and wild animals
• According to surveys, only 2.4% of the population in the Philippines is seropositive for Toxoplasma gondii
• Pigs and rats have a higher prevalence of positive titers for Toxoplasma antibodies at 19% and 8.1%, respectively
• Prevention measures for Toxoplasma gondii infection

  • Protect food from contamination with cat feces
  • Avoid contact with cats for pregnant women
  • Be careful when handling the parasite in the laboratory
  • Wear gloves when gardening or handling soil
  • Don't eat raw or undercooked meat
  • Don't eat raw shellfish
  • Wash kitchen utensils thoroughly
  • Wash all fruits and vegetables before eating
  • Don't drink unpasteurized goat milk or untreated water
  • Cook meat to 66°C before eating
  • Don't feed raw meat to cats
  • Keep cats indoors and change litter boxes daily
  • Cover children's sandboxes when not in use
• Microsporidia


  Obligate intracellular parasites that have been recognized in a variety of animals
• Microsporidia cysts

  • Usually 1-4 µm for medically-important species
  • Contain spores with polar tubules
  • Can survive outside the host
  • Are the dormant form
• Microsporidia trophozoites


  • Small in size, ranging from 1 to 4 µm
  • Found in the cells of the gut epithelium of insects, as well as in the skin, muscles, and other tissues of fish and some other invertebrates
  • Contain a polar tubule or polar filament
• Microsporidia are a group of unicellular eukaryotic parasites that predominantly infect animals
• Clinical manifestations of microsporidia infection

  • Diarrhea
  • Myositis
  • Keratitis
  • Bronchitis
  • Encephalitis
• Gastrointestinal infection is the most common manifestation of microsporidia
• Microsporidia have emerged as opportunistic pathogens in patients with AIDS and other immunocompromising conditions
• The vast majority of microsporidia cases are caused by Enterocytozoon bieneusi, followed by some Encephalitozoon species
• Pneumocystis jiroveci

  Formerly known as Pneumocystis carinii, a fungal pathogen responsible for causing Pneumocystis pneumonia (PCP), primarily affecting immunocompromised individuals
• Pneumocystis jiroveci cysts

  • Spherical structures typically containing 8 intracystic bodies
• Pneumocystis jiroveci trophozoites

  • The active forms of the organism found within the alveolar spaces of the lungs
  • Lack a defined cell wall
  • 1-5 µm, pleomorphic and contain a single nucleus
• Pneumocystis jiroveci is an obligate intracellular pathogen that primarily infects the lungs, specifically targeting the alveolar epithelial cells
• Prevention and control measures for Pneumocystis jiroveci infection

  • Prophylactic antibiotics like TMP-SMX
  • Managing underlying conditions
  • Vaccination against other respiratory infections
  • Infection control practices
  • Education for early detection and treatment
• Loa loa


  A parasitic worm causing African eye worm

  
• First adult Loa loa worm extracted from the eye of a young slave in

  1770 Maribou (Saint Domingue) by Mongin


  
• Parasite described in Angola by Guyot, who gave it the name "Loa" the word for "worm" used by the indigenous population


  1778

  
• Manson discovered the microfilariae of L. loa in the blood and provided the name Filaria diurna due to the periodicity of the parasite


  1891

  
• reported microfilariae in cerebrospinal fluid,

  (1908) Broden and Rodhain

  
• Van Campenhoot established the relationship between edema and L. loa in several patients


  1900
• Robert Thomson Leiper determined that the larval cycle of the worm developed in Chrysops silacea and Chrysops dimidiata


  1912

  
• Chrysops vector of Loa loa

  • Chrysops silacea
  • Chrysops dimidiata
• Chrysops flies


  • Can carry more infective L3 along their proboscis and thorax, serving as a source of natural infective-stage larvae of Loa loa

  
• The Loa loa parasite does not have a trophozoite stage