Comm Eye Health Vol. 26 No. 82 2013 pp 30 - 31. Published online 05 August 2013.

At a glance: the core neglected tropical diseases

Anthony Solomon

Wellcome Trust Intermediate Clinical Fellow, Clinical Research Department, London School of Hygiene & Tropical Medicine, London, UK.


Michael Marks

Wellcome Trust Clinical Research Fellow, Clinical Research Department, London School of Hygiene & Tropical Medicine, London, UK.

Related content

Trachoma

Where

  • Africa
  • Latin America
  • Yemen
  • China
  • India
  • Australia
  • South-East Asia
  • Pacific Islands

(see www.trachomaatlas.org)

How

  • Discharge from infected eyes spreads via fingers, fomites and eye-seeking flies (especially Musca sorbens)
Trachomatous trichiasis. © WHO
Trachomatous trichiasis. © WHO

Who

  • Pre-school-age children have the highest prevalence of active trachoma. The prevalence of blindness from trachoma increases with age

What

  • Inflammation of the conjunctiva (active trachoma)
  • Conjunctival scarring
  • Trichiasis
  • Corneal opacification

Test

  • Clinical diagnosis

Treat

Individual:

  • Tetracycline eye ointment twice daily for 6 weeks, or single dose azithromycin, 20mg/kg (maximum 1g), for active trachoma
  • Surgery for trichiasis

Population:

  • SAFE strategy

Onchocerciasis

Where

  • Africa
  • Latin America
  • Yemen
A woman blinded by onchocerciasis © CBM All rights reserved
A woman blinded by onchocerciasis © CBM All rights reserved

How

  • Acquired by the bite of an infected blackfly (Simulium sp.)

Who

  • People living near rivers where blackflies breed

What

  • Nodules under the skin
  • Pruritus
  • Thickening of skin or loss of skin pigment
  • Punctate keratitis
  • Sclerosing keratitis
  • Uveitis
  • Chorioretinitis
  • Optic atrophy

Test

  • Skin snip
  • Slitlamp examination of eye

Treat

Individual:

  • Ivermectin 150µg/kg once a month for 3 months

Population:

  • Mass distribution of ivermectin

Soil-transmitted helminths

Where

  • Worldwide

(see www.thiswormyworld.org)

Adult female Ascaris  lumbricoides worm © CDC
Adult female Ascaris lumbricoides worm © CDC

How

  • Eggs are passed out in faeces and then swallowed by another host (Ascaris, Trichuris) or develop into infective larvae and penetrate intact skin (hookworm)

Who

  • People living in communities with poor access to water and sanitation
  • People who walk barefoot are at risk of hookworm infection

What

  • Often asymptomatic
  • May contribute to anaemia leading to fatigue and lethargy

Test

  • Stool microscopy for eggs

Treat

Individual:

  • Single dose albendazole 400mg

Population:

  • Mass distribution of albendazole or mebendazole.
  • Improved access to safe methods for disposal of human faeces

Lymphatic filariasis

Where

  • Africa,
  • Asia
  • Latin America
  • Pacific Islands

(see www.thiswormyworld.org)

How

  • Acquired by the bite of infected mosquitoes

Who

  • Children aquire the infection, but sequelae tend to occur in adults
Elephantiasis due to lymphatic filariasis © CDC
Elephantiasis due to lymphatic filariasis © CDC

What

  • Often asymptomatic
  • Enlargement of the limbs, genitals or breasts, with secondary skin changes

Test

  • Examination of night blood smear for microfilariae

Treat

Individual:

  • Albendazole 400mg for 21 days
  • Washing of swollen parts to reduce risk of secondary infection and progression of elephantiasis

Population:

  • Mass distribution of DEC+albendazole, or (if onchocerciasis co-endemic) ivermectin+ albendazole

Schistosomiasis

Where

  • Africa
  • Asia
  • Latin America

(see www.thiswormyworld.org)

How

  • Acquired by contact with standing fresh water (e.g. lakes) in which there are infected snails

Who

  • Children and adults who play, work or undertake chores on the edge of lakes
Dipstick testing to detect haematuria. The sample on the left is negative for haematuria – the other two are both positive. © Swiss Tropical Institute courtesy M Tanner
Dipstick testing to detect haematuria. The sample on the left is negative for haematuria – the other two are both positive. © Swiss Tropical Institute courtesy M Tanner

What

  • Acute infection: fever, itchy rash
  • Chronic infection: often asymptomatic; haematuria, renal failure, bladder cancer (urinary schistosomiasis); liver failure (intestinal schistosomiasis)

Test

  • Urine/stool microscopy for eggs

Treat

Individual:

  • Two doses of praziquantel 20mg/kg taken 6 hours apart after food

Population:

  • Mass distribution of praziquantel
  • Improved access to safe methods for disposal of human faeces
  • Education

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