LEISHMANIA AND LEISHMANIASIS Flashcards
SYMBIOTIC INTERACTIONS
SYMBIOSIS: A CLOSE BIOLOGICAL INTERACTION BETWEEN 2 DIFFERENT SPECIES
TYPES:
- MUTUALISM (A SYMBIOTIC RELATIONSHIP IN WHICH BOTH SPECIES BENEFIT)
- COMMENSALISM (ONE SPECIES BENEFITS WHILE OTHER SPECIES ISN’T AFFECTED)
- PARASITISM (ONE SPECIES, THE PARASITE, BENEFITS WHILE THE OTHER SPECIES, THE HOST, IS HARMED)
KINETOPLASTIDS?
- VERY DIVERGENT GROUP OF ORGANISMS COMING FROM ‘EARLY BRANCHING’ PART OF THE EVOLUTIONARY TREE
- 1 BILLION YEARS OF EVOLUTIONARY DISTANCE WITH OTHER BRANCHES (HUMANS)
- KINETOPLASTID TRYPANOSOMATIDS CONTAINS SEVERAL IMPORTANT PARASITES: AFRICAN TRYPANOSOMES, AMERICAN TRYPANOSOMES, LEISHMANIA SPP
HOW MANY TRYPANOSOMATID HUMAN PARASITES ARE THERE?
3
WHAT ARE THE TRYPANOSOMATID HUMAN PARASITES?
TRYPANOSOMA BRUCEI: CAUSES HAT AND NAGANA, TRANSMITTED BY TSETSE FLIES, LIVES EXTRACELLULARLY AND HAS AN ELABORATE SYSTEM OF ANTIGENIC VARIATION
TRYPANOSOMA CRUZI: CAUSES CHAGAS DISEASE, TRANSMITTED BY BUGS (TRIATOMINE), LIVES INTRACELLULARLY IN THE CYTOPLASM OF VARIOUS CELLS
LEISHMANIA SPP: CAUSATIVE GENT OF LEISHMANIASIS, TRANSMITTED BY SANDFLIES (PHLEBOTOMINAE), LIVES IN THE PHAGOSOMES OF MACROPHAGES (IN HUMANS)
(ALL ARE ON THE WHO NTD LIST)
LEISHMANIASIS; DISEASE BURDEN:
- 350 MILLION PEOPLE LIVE IN ENDEMIC AREAS: 98 ENDEMIC COUNTRIES
- 12 MILLION PEOPLE INFECTED
- 3-5 MILLION CLINICAL CASES
- 2 MILLION NEW CASES EACH YEAR (0.5 MIL ARE VISCERAL)
- 50 000 DEATHS FROM VL (VISCERAL LEISHMANIASIS) PER YEAR
(ABOVE FACTS FROM 2010, NOW 50 000 TO 90 000 NEW CASES OF VL)
—> VISCERA REFERRING TO ORGANS, ESP IN THE TORSO
WHICH PATHOGENS CAUSE VISCERAL LEISHMANIASIS (VL)?
L. INFANTUM AND L. DONOVANI
OTHER NAME FOR VISCERAL LEISHMANIASIS?
KALA-AZAR
FATALITY OF UNTREATED VISCERAL LEISHMANIASIS?
95%
IN WHICH COUNTRIES DOES VISCERAL LEISHMANIASIS MOSTLY OCCUR?
BRAZIL, EAST AFRICA AND INDIA
SYMPTOMS OF VISCERAL LEISHMANIASIS?
- IRREGULAR BOUTS OF FEVER
- WEIGHT LOSS
- ENLARGEMENT OF THE SPLEEN AND LIVER, AND ANAEMIA
CUTANEOUS LEISHMANIASIS?
CUTANEOUS = SKIN
- CAUSED BY > 20 DIFFERENT SPECIES OF LEISHMANIA
- USUALLY NOT FATAL
- MOST COMMON CAUSE OF LEISHMANIASIS
- CAUSES SKIN LESIONS, MAINLY ULCERS ON EXPOSED PARTS OF THE BODY
- USUALLY HEALS WITHIN A FEW MONTHS, BUT LEAVES LIFE-LONG SCARS AND SERIOUS DISABILITY OR STIGMA
- 600 000 - 1 000 000 NEW CASES ANNUALLY
- 95% OF CASE OCCUR IN THE AMERICAS, THE MEDITERRANEAN BASIN, THE MIDDLE EAST AND CENTRAL ASIA
MOST COMMON FORM OF LEISHMANIASIS?
CUTANEOUS LEISHMANIASIS
WHAT IS THE CAUSE OF MUCOCUTANEOUS LEISHMANIASIS?
LEISHMANIA BRAZILIENSIS
MUCOCUTANEOUS LEISHMANIASIS?
- MUCOCUTANEOUS —> AFFECTS SKIN AND MUCUS MEMBRANE
- RARE FORM OF CUTANEOUS LEISHMANIASIS
- LEADS TO PARTIAL OR TOTAL DESTRUCTION OF THE MUCUS MEMBANES OF THE NOSE, MOUTH AND THROAT
- OVER 90% OF CASES OCCUR IN: BOLIVIA, BRAZIL, PERU AND ETHIOPIA
LEISHMANIASIS BURDEN IS LIKELY TO INCREASE OR DECREASE IN THE FUTURE?
INCREASE
LEISHMANIASIS BURDEN IS LIKELY TO INCREASE OR DECREASE IN THE FUTURE?
INCREASE
WHY IS IT PREDICTED THAT THE LEISHMANIASIS BURDEN WILL INCREASE IN THE FUTURE?
DUE TO:
- POPULATION MOBILITY (LEISHMANIASIS EPIDEMICS OFTEN ASOCIATED WITH MIGRATION, THE MOVEMENT OF NON IMMUNE PEOPLE INTO AREAS WITH HIGH PREVALENCE)
- ENVIRONMENTAL CHANGES (CHANGES IN URBANIZATION, HUMAN INCURSION INTO FORESTED AREAS)
- CLIMATE CHANGE (CHANGES IN TEMP, RAINFALL, HUMIDITY, DROUGHT, FAMINE AND FLOOD) CAN HAVE STRONG EFFECTS ON VECTORS AND RESERVOIR HOSTS
HOW MANY TYPES OF LEISHMANIASIS ARE THERE?
3: VISCERAL (AFFECTS THE VISCERA, DEADLY), CUTANEOUS (SKIN, MOST COMMON), MUCOCUTANEOUS (CAUSES TERRIBLE DISFIGUREMENT AND IS THE LEAST COMMON)
WHAT ARE THE 2 LEISHMANIA FORMS THAT INVADE VERTEBRATE IMMUNE CELLS?
PROMASTIGOTE AND AMASTIGOTE
PROMASTIGOTE VS AMASTIGOTE LEISHMANIA FORMS CHARACTERISTICS?
PROMASTIGOTE: INOCULATED INTO THE HOST BY THE SANDFLY, ELONGATED, FLAGELLATED FORM, POWERFUL SWIMMER, INVADES PHAGOCYTIC IMMUNE CELLS (MACROPHAGES ETC)
AMASTIGOTE: FORMED FROM PROMASTIGOTE AFTER ITS FIRST INVASION, SMALL AND ROUND, HAS A VERY SMALL IMMOTILE FLAGELLUM, INVADES PHAGOCYTIC IMMUNE CELLS (MACROPHAGES ETC), INFECTS SANDFLY