| Worm | Notes | Treatment |
|---|---|---|
| Strongyloides stercoralis | Larvae are present in soil and gain access to the body by penetrating the skin |
Features include diarrhoea, abdominal pain, papulovesicular lesions where the skin has been penetrated by infective larvae e.g. soles of feet and buttocks, larva currens: pruritic, linear, urticarial rash, if the larvae migrate to the lungs a pneumonitis similar to Loeffler's syndrome may be triggered | Ivermectin and -bendazoles are used | | Enterobius vermicularis (pinworm) | Threadworm infestation is asymptomatic in around 90% of cases, possible features include perianal itching, particularly at night; girls may have vulval symptoms
Diagnosis may be made by the applying sticky plastic tape to the perianal area and sending it to the laboratory for microscopy to see the eggs | -bendazoles | | Ancylostoma duodenale, Necator americanus (hookworms) | Larvae penetrate skin of feet; gastrointestinal infection → anaemia Thin-shelled ova | -bendazoles | | Loa loa | Transmission by deer fly and mango fly
Causes red itchy swellings below the skin called 'Calabar swellings', may be observed when crossing conjunctivae | Diethylcarbamazine | | Trichinella spiralis | Typically develops after eating raw pork
Features include fever, periorbital oedema and myositis (larvae encyst in muscle) | -bendazoles | | Onchocerca volvulus | Causes 'river blindness'. Spread by female blackflies
Features include blindness, hyperpigmented skin and possible allergic reaction to microfilaria | Ivermectin
”rIVERblindness = IVERmectin” | | Wuchereria bancrofti | Transmission by female mosquito
Causes blockage of lymphatics → elephantiasis | Diethylcarbamazine | | Toxocara canis (dog roundworm) | Transmitted through ingestion of infective eggs.Features include visceral larva migrans and retinal granulomas
”VISCious dogs → blindness” | Diethylcarbamazine | | Ascaris lumbricoides (giant roundworm) | Eggs are visible in faeces
May cause intestinal obstruction and occasional migrate to lung (Loffler's syndrome) | -bendazoles |
| Worm | Notes | Treatment |
|---|---|---|
| Echinococcus granulosus | Transmission through ingestion of eggs in dog faeces. Definite host is dog, which ingests hydatid cysts from sheep, who act as an intermediate host. Often seen in farmers. |
Features include liver cysts and anaphylaxis if cyst ruptures (e.g. during surgical removal) | -bendazoles | | Taenia solium | Often transmitted after eating undercooked pork. Causes cysticercosis and neurocysticercosis, mass lesions in the brain 'swiss cheese appearance' | -bendazoles |
| Worm | Notes | Treatment |
|---|---|---|
| Schistosoma haematobium | Hosted by snails, which release cercariae that penetrate skin. | |
| Causes 'swimmer's itch' - frequency, haematuria. Risk factor for squamous cell bladder cancer | Praziquantel | |
| Paragonimus westermani | Caused by undercooked crabmeat, results in secondary bacterial infection of lungs | Praziquantel |
| *Clonorchis sinensis |
”clonorchis = cholangitis”* | Caused by undercooked fish
Features include biliary tract inflammation. Known risk factor for cholangiocarcinoma | Praziquantel | | Fasciola hepatica (the liver fluke) | May cause biliary obstruction | Triclabendazole |