Infections Lecture 8: parasitic infections and anti-parasitic drugs Flashcards
What are parasites
Living organisms that require intimate prolonged contact with another living organism to meet some of its basic nutritional needs
Unicellular protozoa to complex multicellular helminths
LICE, LEECHES, Scabies, Fleas
What are the main anti parasitic drug classes and sub classes
- Anti Helminths
Anti-nematode
Anti-cestodes
Anti-trematodes - Anti protozoals
Anti-amoebic’s
Antimalarials
what is an anti nematode and give an example of a drug in this class
Sub class of anti-helminths
Role: Immobilises the parasite to cause death
Example: Mebendazole
What is an anti-cestode and give an example of a drug in this class
Sub class of anti-helminths
Role: Interferes with energy metabolism of parasite and glucose synthesis
Example: Niclosamide, Praziquantel (tape worm)
Give an example of an Anti-trematode
Praziquantel
Give an example of anti-protozoal drugs
Metarsoprol- sleeping sickness
Eflornithin- sleeping sickness
Metronidazole- anaerobic bacterial infection
Give examples of anti amoebic and antimalarials
Anti-amoebic- Tinidazole and Metronidazole
Antimalarials- Chloroquine and deoxycycline
Describe what Protozoa and give examples of where it causes diseases
Unicellular eukaryotic organism that feeds on bacteria and particles of nutrients on growing stage
example:
Malaria- parasitic protozoa plasmodium
Intestinal infection
How does malaria normally work
Mosquito is infected and takes blood meal
Infects liver cell which will rupture and infect blood cells
Symptoms begin to show and uninfected mosquito taking infected blood can begin the whole cycle again
What are the three types of malaria
P.falciparum
P.vivax
Adapted to lower temperature
Higher sensitivity to drugs
P.malariae
What are the symptoms of malaria
Common violent fever lasting 6 to 8 hours
Recurs every two to three days
Anaemia and enlargement of spleen develop as disease progresses
Sweating, cough, nausea and vomiting, back pain, fatigue, headache
How do you diagnose malaria
blood film
how do you prevent malaria (prophylaxis)
Malarone: Atovaquone/proguinil hydrochloride
Chloroquine
Quinine + doxycycline
What causes Amoebic dysentry and amoebiasis, what are the symptoms
Entamoeba histolytica
Mild diarrhoea to severe dysentry
Extra intestinal infections like liver abscesses- digests and liquifies human host cells (colon wall, neutrophils, liver cells)
What are the treatment options for amoebic dysentry and amoebiasis
Metronidazole- first line, acute invasive amoebic dysentry
Tinidazole- active against cysts in lumen
What causes Toxoplasmosis and how is it treated
Toxoplasma gondii
Treatment: Self limiting Pyrimethamine Sulphadiazine Clindamycin Corticosteroids
What causes cryptosporidiosis, how its transmitted, symptoms and treatment
Causes: Cryptosporidium paruum
Transmission: spread from water, swimming lakes and pools
Symptoms:
Watery diarrhoea
Dehydration, weight loss, Fever, nausea or vomiting
Treatment:
Usually self limiting but dangerous immunocomprimsied
What are the three different types of parasitic worms (HELMINTHS)
Cestodes- parasitic flatworms (tape worms)
Nematodes- Roundworms- whipworm, hook worms, pin worms
Trematodes- flukes, liver flukes and blood flukes
How are these parasitic worms transmitted
Poorly cooked meat Contaminated water Faeces Insects Eggs or worms can enter through mouth, anus, nose or skin
What are the actions the different helminths have
Most species attach to intestinal tract
Digestive enzymes to dissolve egg shell
Feed off host for nourishment and protection
Asymptomatic for months and years
What are two types of cestodes
Cestodaria
Eucestoda
What are the symptoms of cestodes
Upper abdominal discomfort
Diarrhoea
Loss of appetite
Often asymptomatic
How do you treat cestodes
Taethicides
Niclosmaide
PRAZIQUANTEL
What causes Nematodes (pin and threadworm) and what are the symptoms
Enterobius Vermiculans
Symptoms:
Itching
Scratching, transmit under nails
How do you diagnose Nematodes
Seeing worms in perianal region or scotch tape test- sellotape around anus and look under microscope
How do you treat nematodes
Mebendazole
What are the cause and symptoms of hook worm nematodes
Cause: Ancylostoma duodenale or Necator americanus
Iron deficient anaemia
Diarrhoea, nausea, vomiting
How do you treat hook worm nematodes
Mebendazole
Albendazole
What causes nematode whip worms, symptoms, and treatment
Trichuris trichiura
Light infestation- asymptomatic
Heavy- bloody diarrhoea
Treatment: mebendazole
What causes nematode round worms, its symptoms, complications and treatment
Ascaris lumbricoides
Larval stage- visceral damage, peritonitis and inflammation
Enlargement of liver or spleen, pneumonia
Complications:
obstruction of bolus of worms in bowels
obstruction of bile or pancreatic duct
Treatment:
Mebendazole
How do you treat headline or scabies
Dimeticone lotion or liquid
Permethrin or ivermectin
