Symbiosis- living together, a special relationship between two species necessary for the survival of at least one of the two organisms. It is not mutual or unilateral physiologic dependency but living together without any reference to benefit or damage to symbionts. There are four types: commensalism, phoresis, mutualism and parasitism.
Symbiont- an organism that spends a portion of or all of its life intimately associated with another living organism of a different species.
Commensalism- One organism lives at the expense of another but cause no harm (pilotfish and shark) (+,0)
Phoresis- No physiological dependency is involved. Mechanically carried (0,0) EX: Sexton beetle-phoretic
Mutualism- Mutually beneficial relation (termites and intestinal flagellate) (+,+) Mutually beneficial relation (Clown fish and sea anemone) (+,+)
Parasitism- A guest who uses ones resources to live. An organism that lives on (infest) or in (infect) the host. An organism that nourishes itself at the expense of the host without destroying it as rapidly as predator does. An organism that inflicts some degree of damage to host. (+,-)
Facultative parasite- Opportunistic. They are free living until they are placed in a situation conducive to becoming a parasite. EX: Amoeba Naegleria eats microbes but when opportunity comes infects humans.
Obligatory parasite- Completely dependent on host for all or part of its life cycle. Two types: Permanent and Temporary. Permanent EX: tapeworms in the intestine. Temporary EX: mosquitoes, leeches and ticks.
Endoparasite- lives within the host’s body (infection).
Ectoparasite- lives attached to outside (infestation).
Definitive host- in which parasite attains sexual maturity while inside.
Intermediate host- temporary host necessary for completion of parasite life cycle.
Transfer host- not necessary, can serve as temporary refugee.
Vector- serves as intermediate host that transmit the parasite or disease, Arthropods.
Reservoir- infected animals that serve as source of infection. Three types: sylvatic, domestic, and zoonosis.
Brood parasitism-birds lay their eggs in the nests of others, sparing themselves the expense of rearing their own young. Decline of song bird populations

EPIDEMIOLOGYGeographic Distribution | Enterobius Vermicularis (pinworm)Occurs Worldwide (Global). Cold climatesLess bathing, decrease in changing clothesGuam 1%, Amsterdam 100%, US 33%1st common nematode in U.S. | Dracunculus Medinensis Orient step wellsAfrican ponds of stagnant waterUsually standing ankle-deep in water, below water lineLarvae deposited in waterCopepods infested with larvae in drinking waterEndemic: Africa, Asia, West Indies, BrazilUS: infection in raccoon, human infection not seen. | Trichuris Trichiura (whipworm)Occurs worldwide (Global). Most frequent in tropical countries. Infection common in warm moist areasSouthern U.S.-20-25% most low worm burdens.Some parts of Asia-50-80%Increased prevalence among primary age school children.Common where night soil is used or where there is defecation on soil.3rd most common nematode in world, and 2nd in U.S. | Wucheria BancroftiWidely distributed in tropics and subtropics (Central Africa, India, Asia, Pacific islands)800 million at risk80 million infectedIndia having by far the largest number of cases. Vectors (insects ex. Mosquitoes) | Ascaris Lumbricoides (Giant Roundworm)Most common nematode infection in world. (Global)Central and South America 45%Southern US 1-12%Warm moist (humid) climates where night soil is used.All infected people of China produce 18,000 tons of eggs/year.Most prevalence in children between 5-9 years. | Loa LoaLimited to the African equatorial rain forest and southern Sudan. The vector breeds in muddy ponds and swamps; not surprisingly, infection rates are highest in these regions. | HookwormsBoth species present in tropics and subtropics. (Global)Both found in U.STemperature and rainfall-great influenceRainfall of 30-50” and 75-85 degrees ideal for development of eggs and larvaeSpread or contact with night soil/contaminated soil. All ages susceptibleFarmersDooryard defecationExpectorationShoe wearing | Onchocerca VolvulusApproximately 96% of the cases are in tropical Africa. Infection is common among workers on highland coffee plantations. Cases usually occur in areas with highland. | Strongyloids StercoralisOccurs worldwide (global). The most estimated cases is 21 million in Asia and there have been 400,000 in North America. The free-living forms thrive best in warm, moist climates where sanitation is substandard. | Brugia MalayiOccurs in the pacific geographic range extending from China, Japan, Taiwan, Malaysia, and Indonesia. Is found most often in low-lying regions, which provide optimal breeding conditions of the vectors. | Trichinella SpiralisMost commonly occurs in Europe and the United States, where there are estimated to be 150,000 to 300,000 cases a year. The disease is rare in parts of the tropics and subtropics b/c of diet. | |

EPIDEMIOLOGYMode of Infection | Enterobius Vermicularis (pinworm)TransmissionDirect: anus to mouthIndirect: airborne eggs and fomites | Dracunculus MedinensisCopepods infested with larvae in drinking water | Trichuris Trichiura (whipworm)Human ingest infective egg. (Usually from hand to mouth and comes from soil.) | Wucheria BancroftiCulex, Anopheles, Sedes, Mansonia(mosquitos)Microfilaria are not sheathed | Ascaris Lumbricoides (Giant Roundworm)Human ingest infective egg. (Usually from hand to mouth and comes from soil.) | Loa LoaThe intermediate host is a horse or deer fly and it is infected when it ingest microfilaria in a blood meal | HookwormsFiliform larvae penetrate skin of human. | Onchocerca VolvulusMicrofilarias are ingested by a black fly when it feeds. | Strongyloids StercoralisFiliform larvae penetrate skin of human. | Brugia MalayiAnopheles, Aedes, Mansonia(mosquitos) Microfilaria are sheathed | Trichinella SpiralisEating of raw meat infected with the eggs. | |

PATHOLOGY & SYMPTOMOLOGY | Enterobius Vermicularis (pinworm)1.Large intestineAttachment-Irritation -Inflammation-Necrosis -Appendicitis 2.Perianal area-Severe puritus (itching)-Secondary infection-Benign tumors3.Vagina-Vaginitis-Salpingitis-Pain-resembles gonorrheaToxic metabolites-Nervousness -Insomnia-Irritability -Convulsions | Dracunculus Medinensis * Major problem: Secondary infections of the blister * Infections of deep structures * Tendons * Bones * Joints (20% have deformity of joint) | Trichuris Trichiura (whipworm)Large intestine-Attached to gut wall, feeds on cells, rupture posterior wall and penetration into lumen -Results in tissue injury, secondary infection, hemorrhage, local abdominal pain, loss of appetite-Heavy infections lead to anemia, dysentery, fever due to toxic metabolites, rectal prolapse (rectum exposed) | Wucheria Bancrofti * Asymptomatic * 70% carriers * Hidden damage to lymphatic system and kidneys * Inflammation * Headache * Acute filariases * 25% * Eosinophilia * Urticaria (hives or rashes) * Lymphadenitis (pain) * Attacks of filarial fever * Nausea * Vomiting * Chronic filariases * 1-54% * Elephantiasis * Extreme hypersensitivity * Long in developing-20yrs * Repeated infections necessary * Affect lower genitalia, lower appendages | Ascaris Lumbricoides (Giant Roundworm) * Lungs * Petechial hemorrhage * Serocellular exudate * Cough * Allergic reaction to molting fluid * Asthma like symptoms * Hives * Small intestines * Normal-inhabits lumen of the gut * Abnormal-dangerous outcomes * Intestinal obstruction * Appendicitis * Migration (pancreatic duct, bile duct, esophagus- mouth, eustachian tube-ear and trachea-respiratory obstruction) * Penetration of gut wall-peritonitis | Loa LoaCauses the skin and eye disease Loa Loa Filariasis, also known as Loiasis, Calabar Swelling, Fugitive Swelling and Tropical SwellingLoa Loa infects human host by migrating through subcutaneous tissue such as back, chest, groin, scalp and eye.The parasite causes infection wherever they travel, and if they stay local, the host will suffer from local infection known as Calabar Swellings | Hookworms * Larval penetration (puritis, edema, erythema) * If reinfection occurs allergic reaction, hypersensitivity * Larval migration * Adult attachment * Blood loss * Chronic disease * Small lesion to popule or pimple to vesicle or fluid filled same as puritus, edema, erythema * Reinfection=ground itch * Larval migration-lungs * Usually mild damage due to trickle infection * Adults-attachment/reattachment damage * Results in inflammation, tissue damage, ulceration, hemorrhage: abdominal pain, diarrhea * Blood loss * Iron deficiency anemia, hypochromic, microcytic | Onchocerca Volvulus * EyesAdult worms in head area-microfilaria migrate through eyes-cornea damage-blindness * Skin Loss of elasticity and hanging groin | Strongyloids Stercoralis * Cutaneous-slight hemorrhaging-swelling-intense itching (ground itch)-occasionally severe inflammation * Pulmonary (lungs)-burning sensation in the chest-a cough-other symptoms of bronchial pneumonia * Intestinal-moderate to heavy infections produce pain and intense burning in the abdominal area-nausea-intermittent diarrhea -Long lasting infection results in chronic dysentery and weight loss | Brugia MalayiLymphadenitis (retrograde) in inguinal area, foot and ankle-no pulmonary involvement. | Trichinella SpiralisThree clinical phases * 1) mild, following penetration of adult females into the mucosa and submucosa (12hrs to 2 days after ingestion)-nausea-fever-profuse perspiration -diarrhea * 2) severe, during migration of larvae (last for 3 weeks)-symptoms resembling such diseases as rheumatism, pneumonia, encephalitis, pleurisy, meningitis, myocarditis, and peritonitis * 3) moderate, after penetration and encapsulation of larvae in muscle cells-intense muscle pain-difficulty in breathing-swelling of facial muscles -weakening of blood pressure and pulse-heart damage-nervous disorders, including hallucinations-death may result from heart failure, respiratory complications, peritonitis, or cerebral involvement. | |

DIAGNOSIS | Enterobius Vermicularis (pinworm)Anal swabScotch tape on anus at nightfemale worm in fecesPreservation-ROH, Vinegar | Dracunculus MedinensisObservation of female beneath the skinExamination of ulcers | Trichuris Trichiura (whipworm)DiagnosisFecal smearEggs 50 X 20 micronsBarrel shape w/mucus plugs on endsStained brownProctoscopic exam | Wucheria Bancrofti * Blood examSample taken from 10 pm to 2 pmThick smearKnott’s concentration methodLook for microfilaria * ImmunoassaySkin testComplement fixation * Skin biopsy | Ascaris Lumbricoides (Giant Roundworm)Fecal smear | Loa LoaObservationHistory of exposureMicrofilaria in bloodSkin swellings (nodules) | HookwormsFecal smear | Onchocerca VolvulusSkin biopsy | Strongyloids StercoralisFecal smear | Brugia Malayi * Etiological examinationStained thick blood smear: first choice of methodsBlood drop microscopy: used in the field * Hetrazan induced method * Lymph node biopsy | Trichinella SpiralisDiagnostic procedure is the demonstration of live larvae in a specimen of biopsied muscle. | |

TREATMENT | Enterobius Vermicularis (pinworm)Degenerative changes in gut, muscle, depolarizationTreatment:Albendazole 2 treatments2 weeks apartCan’t use on pregnant women b/c of Teratogen in the drug | Dracunculus MedinensisMatch stick and rubber bandMetronidazoleSurgical removal | Trichuris Trichiura (whipworm)TreatmentMebendazole: 100 mg 2xd for 4d | Wucheria BancroftiTreatment of filariasis involves two components:Getting rid of the microfilariae in people's bloodMaintaining careful hygiene in infected persons to reduce the incidence and severity of secondary (e.g., bacterial) infections. Psychotherapy * Diethylcarmabizine, a derivative of piperazine, used as antihelminthreduces microfilariae concentrations and kills adult worms * Microfilarial drug ivermectin kills the microfilariae produced by adult worms * AlbendazoleChronic early bandage, late surgery | Ascaris Lumbricoides (Giant Roundworm)AlbendazolePyrantel pamoatePiperazine citrate | Loa LoaSurgical removal of Calabar swellingsDiethycabamazine or ivermectin | HookwormsFecal smearMebendazole, albendazole, pyrental pamoate | Onchocerca VolvulusNodulectomyDiethycarbamazine | Strongyloids StercoralisOral administration of 400mg albendazole daily over a period of 3 consecutive days is the therapy of choice. | Brugia MalayiTreatment of filariasis involves two components:Getting rid of the microfilariae in people's bloodMaintaining careful hygiene in infected persons to reduce the incidence and severity of secondary (e.g., bacterial) infections. Psychotherapy• Diethylcarmabizine, a derivative of piperazine, used as antihelminthreduces microfilariae concentrations and kills adult worms • Microfilarial drug ivermectin kills the microfilariae produced by adult worms • AlbendazoleChronic early bandage, late surgery | Trichinella SpiralisNo satisfactory chemotherapeutic regimen has been devised. The therapeutic value of albendazole and mebendazole remains inconclusive. Bed rest and administration of analgesics are beneficial. | |

PREVENTION | Enterobius Vermicularis (pinworm)Eggs-sunlight/UV lightPersonal hygieneMass chemotherapy | Dracunculus MedinensisKeep infected water quarantinedChemically treat water to kill copepods | Trichuris Trichiura (whipworm)Sanitary fecal disposalProper use of night soilPersonal hygiene | Wucheria Bancroftiavoid mosquito bitesSleep under a bed netWear long sleeves and trousersWear insect repellent on exposed skin, especially at nightVector control:Covering water-storage containers and improving waste-water and solid-waste treatment systems can help by reducing the amount of standing water in which mosquitoes can lay eggs.Killing eggs (oviciding) and killing or disrupting larva (larviciding) in bodies of stagnant water can further reduce mosquito populations. | Ascaris Lumbricoides (Giant Roundworm)Sanitary facilityProper use of night soilWash food | Loa LoaSurgical and chemical treatment of patients to prevent further spread of the disease, control of the insect vector population, and protection and education of potential victims. Protective netting and screening and use of insect repellents effectively shield the fly. | HookwormsMass treatmentEducationSanitary disposal of fecesPersonal hygieneShoes | Onchocerca VolvulusRemove vectorTreat infected population | Strongyloids Stercoralis Sanitary disposal of human excrement, protection of skin from contact with contamination soil, and appropriate treatment in cases of autoinfection. | Brugia Malayiavoid mosquito bitesSleep under a bed netWear long sleeves and trousersWear insect repellent on exposed skin, especially at nightVector control:Covering water-storage containers and improving waste-water and solid-waste treatment systems can help by reducing the amount of standing water in which mosquitoes can lay eggs.Killing eggs (oviciding) and killing or disrupting larva (larviciding) in bodies of stagnant water can further reduce mosquito populations. | Trichinella SpiralisEducation. Laws governing pork production be strengthened and should first be sterilized. Public informed to cook pork and meat thoroughly in order to kill larvae. Prevention also includes not eating meat products especially pork. | |