Dictionary of Tropical Medicine

B-Lymphocyte (or B-Cell)

A type of white blood cell that circulates through the body and is able to detect the presence of the foreign agents. Once exposed to an antigen on the agent, these cells differentiate into plasma cells to produce antibody.

Bacteraemia

Presence of bacteria in the blood stream without multiplication.

Bacteria

Single or multicellular organisms belonging to Kingdom Prokaryotae. These single cell prokaryotic organisms are often coccoid or rod- shaped but can also be curved, pleomorphic or spiral. They can be Gram positive, Gram negative or Gram variable.

Bacteriophage

A virus which parasitises a bacterium; a bacterial virus.

Barmah Forest virus

A mosquito-borne arbovirus causing symptoms similar to Ross River virus infection in Australia. (See also Ross River virus).

Basal Cell Carcinoma

A generally slow growing malignant epithelial tumour, which has potential to invade and metastasise, especially if untreated.

Bat

Winged mammals which can be associated with the transmission of rabies, Lyssavirus and Australian Bat Morbillivirus infections to humans. Most species are insectivorous or fruit-eaters, but the vampire bats of Latin America feed on mammalian blood.

BCG

(Bacillus Calmette-Gurin) A live attenuated vaccine used in tuberculosis.

Bedbugs

Blood sucking hemipterans belonging to the genus Cimex. Not important in the transmission of disease but can cause irritating allergic response to their saliva.

Benign

Non-malignant neoplasm; a neoplasm that is not locally invasive and does not spread to distant sites (metastasise).

Beta lactams

Antibiotics with a beta-lactam ring in their molecular structure, including the penicillins and the cephalosporins. Act on penicillin binding proteins in the mucopeptides of the bacterial cell wall. Can be destroyed by bacterial beta-lactamases.

Betelnut

An areca-nut chewed in India, south east Asia and the Pacific, including Papua New Guinea, as a stimulant. Betelnut can have side effects such a staining of teeth and is possibly carcinogenic.

Biguanides

Group of antimalarial drugs which includes Proguanil (Paludrine) used for malaria prophylaxis.

Bilharzia

Schistosomiasis; a diseases caused by a parasitic trematode and acquired by contact with water infected with cercariae shed by the snail intermediate host.

Bioassay

Assessment of the efficacy and persistence of an insecticidal treatment by exposing mosquitoes of known susceptibility to a treated surface or area for a standard period of time.

Biological Control

Use of natural, indigenous predators or organisms to control medically important insects.

Biopsy

A surgical process in which a small piece of tissue is cut out or otherwise sampled, e.g. through a needle biopsy, to enable a diagnosis to be made.

Bipolar staining

The effect of the two ends of a bacillus staining while the centre of the rod remains unstained (eg in Yersinia pestis, the cause of Bubonic Plague) when stained with Giemsa stain.

Bite

The use of teeth or other similar hard substance to puncture the skin of a victim, possibly resulting in the introduction of venom (eg snake bite). c.f. poison and sting.

Blackfly

Blood-sucking flies belonging to the genus Simulium. Includes the vectors of human Onchocerciasis (River Blindness) in parts of Africa and Latin America.

Blastomycosis

A deep (systemic) mycotic infection caused by dimorphic fungi. North American Blastomycosis caused by Blastomyces dermatitidis in N. America and tropical Africa while Paracoccidioides braziliensis causes S. American Blastomycosis in South America.

Blubber

Colloquial term for Catostylus, the most common rhizostome jellyfish in Australia.

Blue-ringed octopus

Colloquial term for Hapalochlaena spp.

Bluebottle

Colloquial term for the single-tentacled Physalia utriculus.

Boomerang leg

A condition whereby the tibiae are curved resulting from such conditions as congenital syphilis or yaws. Also known as sabre tibiae.

Boomslang

An African tree snake belonging to the Family Colubridae. It is highly poisonous, the venom being haemotoxic in nature and causing profuse bleeding. Bites are, however, rare as the snake is back fanged.

Borrelia

A genus of spirochaetes causing Lyme Disease (Borrelia burgdorferi) and Relapsing fever (B. recurrentis; B. duttoni). These zoonotic infections are transmitted through the bites of argassid ticks (tampans).

Bothrium

A longitudinal groove in the scolex of pseudophyllidean tapeworms.

Box-jellyfish

Colloquial term used by most Australians to refer to Chironex fleckeri, but which actually includes every species of the Class Cubozoa.

Bromeliad

A plant in the family which includes pineapples. They often have small collections of water at the base of the leaves and are favoured breeding places of Aedes aegypti and other mosquitoes.

Brood capsule

A small cyst attached to a germinal layer of the hydatid, containing many protoscolices.

Brown snake

A poisonous snake found on the mainland of Australia. It belongs to the family Elapidae and is extremely venomous, having a potent neurotoxin.

Brucellosis

A zoonotic disease of humans contracted from goats, sheep, pigs or cattle. Can be caused by Brucella melitensis, B. abortus or B. suis Unpasteurised milk can be a source for human infection. Often presents as a PUO.

Bubo

Enlarged lymph gland containing pus. Often in the groin. Seen especially in Bubonic Plague, Lymphogranuloma venereum and chancroid.

Bubonic Plague

A severe illness caused by the Gram negative rod, Yersinia pestis. The reservoirs for the infection are various species of rodent and the bacteria are transmitted through the bite of the rat flea, Xenopsylla cheopis. Patients present with enlarged lymph glands (buboes) often in the groin or armpit. Can become septicaemic or develop into a pneumonia (Pneumonic Plague) and spread by droplet. Also known in the past as The Black Death.

Buccal capsule

The thickening of the cuticular lining of buccal cavity; buccal capsule may be large, small, vestigial or absent. In some nematodes, the cuticle lining within the buccal capsule may be modified to be chitinous teeth or cutting plates as in Ancylostomatidae or a stylet as in Trichinelloidea.

Bullrout

A venomous fresh water fish similar to stonefish. See Scorpaenidae.

Burkitts lymphoma

Lymphoid tumour associated with Epstein-Barr (EB) virus. Especially common in malaria endemic areas, such as Africa and Papua New Guinea. May be associated with the immunosuppressive effects of the malaria infection.

Bursa

An umbrella-like expansion of the cuticle at the posterior end of some male nematodes as in Ancylostomatidae and Metastrongylidae. The bursa is supported by elongated stalks called "rays". The shape and size of the bursa and the arrangement and size of the rays are used for identification of the nematodes

Butterfly cod

See Scorpaenidae.

Button spider

A South African spider similar to the Redback spider of Australia and the Black Widow spider of America. Belongs to the species Latrodectus indistinctus.