Lecture 16 - International health Flashcards
what are the classes of the main neglected tropical diseases (NTDs)?
- protozoan infections
- bacterial infections
- helminth infections
- viral infections
give examples of neglected protozoan infections
- HAT
- chagas disease
- leishmaniasis
give examples of neglected bacterial infections
- buruli ulcer
- leprosy
- trachoma
give examples of neglected helminth infections
- ascariasis
- hookworm infection
- trichuriasis
- schistosomiasis
give examples of neglected viral infections
- dengue
- rabies
what are DALYs?
Disability Adjusted Life Years
how many DALYs are lost from NTDs?
56.6m
where is the highest prevalence of neglected tropical diseases?
Sub-Saharan Africa
what 3 NTDs have the most cases in Sub-Saharan Africa?
1) hookworm
2) ascariasis
3) schistosomiasis
what is schistosomiasis?
- also known as snail fever/bilharzia
- disease caused by parasitic flatworms called schistosomes
- affects the poorest people
- serious because anyone who swims in fresh water in Africa/does irrigation/domestic duties could become infected
describe the life cycle of schistosomes
1) eggs are eliminated with faeces/urine
2) eggs hatch if they are deposited in fresh water
3) larvae infect snails and reproduce
4) snails body is taken over and massive sexual reproduction occurs
5) larvae are released as free living larvae in thousands from each snail
6) each larvae can penetrate unbroken human skin
7) larvae migrate around the body to liver and mature into adults
8) adults pair in liver
9) adults migrate to blood vessels around the bladder and intestine and lay eggs (to be eliminated)
what are the health consequences of schistosomiasis?
- blood in urine
- malnutrition
- anaemia
- growth retardation
- cognitive impairment
- increased susceptibility to other infections
- inflammation of organs
what are the life threatening consequences of schistosomiasis?
- bladder cancer
- portal hypertension
- vomiting of blood
what is the treatment of schistosomiasis?
praziquantel: kills adult schistosomes
- off-patent = significant price cuts in 1990s making it more affordable
what is female genital schistosomiasis?
- urinary schistosomiasis in females causes genital lesions as eggs are trapped in the cervix
- lesions have been linked to increased risk of HIV
- higher than expected HIV in Mozambique, Malawi, S. Africa and Tanzania
- treatment of young females is essential
what are soil-transmitted helminth (STH) infections?
- “worms”
- lead to stunting and decreased school performance in children
- most common infections of children worldwide
- estimated that 44m pregnant women harbour hookworm infections so deworming greatly improves pregnancy outcomes, avoiding: increased maternal mortality, low birthweight
what are the treatments of STH infections?
- albendazole
- mebendazole
what is onchocerciasis?
- also known as river blindness
- uses blackfly vector
- causes blindness and severe skin disease
- 37m infected (99% in Africa)
what are the treatments and controls of onchocerciasis?
- treatment = mectizan
- control of blackflies = insecticides
what is APOC?
Africal Programme for Onchocerciasis Control
what is lymphatic filariasis?
- transmitted by mosquitos
- 120m infected
- 40m with symptoms
- annual treatment prevents transmission
what are the treatments of lymphatic filariasis?
- albendazole with mectizan in Africa
- albendazole with DEC in Asia
what is blinding trachoma?
- world’s leading cause of preventable blindness
- 84m infected
- 8m visually impaired
what is the treatment of blinding trachoma?
zithromax
what is albendazole used to treat?
helminths and LF
what is melbendazole used to treat?
helminths
what is mectizan used to treat?
oncho and LF
what is praziquantel used to treat?
schistosomiasis
what is combined therapy used to treat?
leprosy
what is zithromax used to treat?
blinding trachoma
what is the WHO recommended strategy for treating helminths, LF, schistosomiasis, oncho and trachoma?
mass drug administration (MDA) in areas where prevalence rates are above certain thresholds because diagnosis and treatment is impossible due to diagnostic costs but the drugs are safe and effective
how are NTDs controlled?
- mapping
- strategic plans
- health education material
- training at all levels
- distribution of drugs
- treatments in schools/communities
how do donated drugs get delivered to those who need them?
- political will
- training
- transport
- community drug volunteers
- collaboration
- money: costs approx $250m/year to deliver drugs
list 4 success stories in the control of NTDs
- LF in Zanzibar
- trachoma in Morocco
- guinea worm globally
- schistosomiasis in Egypt
what is dengue?
- mosquito borne viral disease with a global tropical distribution
how is dengue controlled?
- diagnosis and case management
- surveillance and outbreak response
- sustainable vector control
- possible vaccine in future
- research
what is rabies?
- disease causing 55,000 human deaths/year in Africa and Asia
- once symptoms develop death rate is 100%
- most commonly from dog bites
how is rabies controlled?
- dog vaccination
- human management of dogs
- vaccination immediately after exposure
- elimination targets
what is buruli ulcer?
chronic skin disease that is endemic in 33 countries but highest in Ghana, Gabon and Australia
- 5,000 cases/year
- poor knowledge and reporting
how is buruli ulcer controlled?
- training of health workers
- early case detection
- antibiotic treatment
- surgery if necessary
what is leprosy?
- a contagious disease that affects the skin, mucous membranes, and nerves
- also known as Hansen disease
- chronic disease
- incubation period of 5 years
- 95% of population have natural immunity
how is leprosy prevented and controlled?
1) early detection and multi-drug therapy (MDT)
2) capacity building to sustain control
3) research
what is podoconiosis?
- also known as elephantiasis
- swelling of feet and lower legs
- essentially no treatment
what is trypanosomiasis sleeping sickness?
- transmitted by the Tsetse fly which has a sharp bite
- can be both chronic and acute killer
how is sleeping sickness controlled?
- early diagnosis
- therapy for infected people
- Tsetse control (baited traps and systemic insecticides in cattle in Uganda)
