Dictionary of Tropical Medicine

Enterobius vermicularis

A small nematode parasite of humans. Also known as pinworm, threadworm or seatworm. Infection often associated with anal pruritis, especially in children.


See expired air resuscitation.


One of the severe African viral haemorrhagic fevers.


See external cardiac compression.

Ecological area

A well defined geographical area, for example a tropical rain forest, characterised by certain assemblages of plants and animals (including insects).


The outer tissues of an organism from which nerve, gland and nematocyst cells will develop.

Egg capsule

A membranous structure containing eggs of a tapeworm, in the absence of uterus (e.g. in Dipylidium caninum).


Fertilised female reproductive cells (ova) with nutrient material, e.g. those deposited by female mosquitoes and developing in water to produce free-swimming larvae.


Entomological Inoculation Rate.


Family of snakes which includes poisonous snakes with fixed front fangs such as the cobras, the mambas and the Australian Tiger snakes.


Marked swelling and inflammation of the lymphatics, associated with hypertrophy and thickening of the overlying skins and subcutaneous tissues, usually in the lower limbs and external genitalia. While not exclusive to filariasis, it is seen often in chronic filariasis due to Wuchereria bancrofti and Brugia malayi. The affected areas often taken on a woody character and can be extensive. See also filariasis.


Wasting of body tissues. Thin (same as cachexia).


A blockage of blood vessels either by blood clot, fat or air; see gas embolism.


A drug used in the treatment of invasive intestinal or extraintestinal amoebiasis caused by Entamoeba histolytica. No longer widely used due to its toxicity. Dehydroemetine is also effective and is somewhat less toxic.


The study of the diseases of travellers or Travel Medicine.


Usual frequency/constant presence of disease occurrence. The habitual presence of disease or the infectious agent within the given geographic area; may also refer to the usual prevalence of a given disease within such area.


The inner tissues of an organism.

Endogenous budding

Inward development from the germinal layer of a hydatid resulting in the formation of a daughter cyst or brood capsule.


Preferring to feed indoors.


Preferring to rest indoors.


Toxin released when certain bacterial species (especially the Gram negative rods) die. Symptoms not specific to the bacterial species (eg endotoxic shock in Gram negative rod septicaemias).

Enteric Fever

Typhoid and Paratyphoid. Septicaemic diseases caused by Salmonella typhi and Salmonella paratyphi.


The injection of a venom into the tissues by teeth, spines, miniature harpoons (nematocysts) or drills. c.f. bite and sting.

Environmental manipulation

Making temporary changes to the environment with the objective of reducing vector abundance.

Environmental modification

Making permanent changes to the environment with the objective of reducing vector abundance.


Usually a protein made by the body to make chemical reactions take place at a faster rate or to cause a colour change in a laboratory test.


An increase in the number of eosinophils in the blood and associated with an allergic response or an invasive helminth infection.

Eosinophilic enteritis

A disease in patients presenting with severe abdominal colic, evanescent small bowel obstruction and a peripheral blood eosinophilia. Zoonotic hookworms, e.g. Ancyclostoma caninum, are believed to be the causative agent, as described by Dr John Croese and others from northern Queensland.


Unusual frequent occurrence of disease in the light of past experience. The occurrence in a community of region of a group of illness (or an outbreak) of similar nature, clearly in excess of normal expectancy and derived from a common or a propagated source. The number of cases indicating presence of an epidemic will vary according to the infectious agent, size and type of population exposed, previous experience or lack of exposure to the disease, time and place of occurrence. Epidemicity is thus relative to usual frequency of the disease in the same area, among the specified population, at the same season of the year. A single case of a communicable disease long absent from the population (as Smallpox, in Boston) or first invasion by a disease not previously recognised in the area (as American Trypanosomiasis, in Arizona) is to be considered sufficient evidence of an epidemic to require immediate reporting and full investigation.

Epidemic polyarthritis

Disease common in Australia and caused by the Ross River Virus, an arbovirus transmitted by mosquitoes.


A science concerned with describing the pattern of occurrence of disease in a population and determining the factors which influence disease prevalence and distribution with the ultimate objective of providing the basis of control of prevention.

Epidermoid carcinoma

Squamous cell carcinoma; cancer of squamous epithelium.


See also Tefanoquine. An anti-relapse drug used to prevent relapses in malaria due to Plasmodium vivax or P. ovale. When used with a chemotherapeutic drug such as chloroquine for these malaria species, it thus can achieve a radical cure.


Removal of tissue.

Excision biopsy

A biopsy of a lesion for the purposes of diagnosis in which the whole lesion is excised.

Excretory pore

An opening of the excretory system, normally situated on the ventral side at the anterior part of the body (e.g. in trematode miracidia).

Exit traps

Devices typically placed over doors and windows of houses or animal shelters to catch mosquitoes leaving these buildings.

Exogenous budding

Outward or external development from the germinal layer of a larval cestode.


Preferring to feed outdoors.


Preferring to rest outdoors.


A toxin secreted by certain bacterial species or strains into the surrounding medium during growth. Often cause clinical features very specific to the disease (eg tetanus, diphtheria, cholera). Exotoxins secreted by enteric organisms often termed enterotoxins.

Expired air resuscitation

The use of expired (used) air blown from a rescuer into the airway and lungs of an unconscious victim who is not breathing, sufficient to sustain his life.

External cardiac compression

Compression of the outside of the sternum and ribs, effectively emptying and filling the heart to push blood through arteries to supply oxygen to the body - particularly to the brain.