Mycology 2 Flashcards
Phylum: MICROSPORIDIA (Microspora)
➢Obligate or facultative? intracellular or extracellular? parasites
➢Infect some or every? major animal group: nearly all of the invertebrate phyla, including unicellular organisms, five classes of vertebrates including mammals. However, the greatest numbers of microsporidian species infect ? and ?.
➢Originally thought to be basal amitochondriate eukaryotes, now known to be related to ? (recall that stramenopiles slide)
➢All microsporidia are ?-forming. Spores are the resistant infectious stages capable of surviving ? environmental conditions.
➢At present more than 1,200 species belonging to 143 genera are recognised. With more species being described frequently.
➢? parasites: many have massively reduced genome sizes, with loss of many essential biochemical pathway -no turning back-
➢Obligate Fungal Parasites !! ** Still ? **!!
Phylum: MICROSPORIDIA (Microspora)
➢Obligate intracellular parasites
➢Infect every major animal group: nearly all of the invertebrate phyla, including unicellular organisms, five classes of vertebrates including mammals. However, the greatest numbers of microsporidian species infect arthropods and fish
➢Originally thought to be basal amitochondriate eukaryotes, now known to be related to “FUNGI” (recall that stramenopiles slide)
➢All microsporidia are spore-forming. Spores are the resistant infectious stages capable of surviving external environmental conditions.
➢At present more than 1,200 species belonging to 143 genera are recognised. With more species being described frequently.
➢Ultimate parasites: many have massively reduced genome sizes, with loss of many essential biochemical pathway -no turning back-
➢Obligate Fungal Parasites !! ** Still oppurtunistic **!!
Generalized mature microsporidian spore
Why are we interested in microsporidia?
➢Microsporidia are known to infect arthropods and fish, many species of which are ? important e.g. bees, silkworm (Pébrine) and many fish species
➢Microsporidian infections can cause high mortalities in commercially important cultured species (aquatic and terrestrial) and diseases in companion animals
➢Microsporidia are very opportunistic and can create ? or ? diseases (shrimp, crabs etc) and are also considered zoonotic pathogens of man
➢ * ? * may reduce host fitness (secondary infections)
➢Microsporidian-infected produce is often unmarketable, causing considerable
? loss
➢As microsporidia can infect humans. Food produced for human consumption should be free of microsporidian parasites
➢Disease prevention. Spores are very ? and difficult to remove from an environment once introduced. Knowledge of life cycles/hosts etc. may prevent disease occurrence
➢Can be used as ? agents to control pest species
Why are we interested in microsporidia?
➢Microsporidia are known to infect arthropods and fish, many species of which are commercially important e.g. bees, silkworm (Pébrine) and many fish species
➢Microsporidian infections can cause high mortalities in commercially important cultured species (aquatic and terrestrial) and diseases in companion animals
➢Microsporidia are very opportunistic and can create new or emerging diseases (shrimp, crabs etc) and are also considered zoonotic pathogens of man
➢ * Chronic infections * may reduce host fitness (secondary infections)
➢Microsporidian-infected produce is often unmarketable, causing considerable
financial loss
➢As microsporidia can infect humans. Food produced for human consumption should be free of microsporidian parasites
➢Disease prevention. Spores are very resistant and difficult to remove from an environment once introduced. Knowledge of life cycles/hosts etc. may prevent disease occurrence
➢Can be used as beneficial agents to control pest species
Example 1. Nosema apis infecting honeybees (horizontal (direct) transmission)
** Chronic infection
Reduced impact to host **
Example 1. does not rely on the death of the host for propagation, however host species suffer reduced fitness and death can result. Many examples including the human-infecting microsporidian
? bieneusi and ? cuniculi (Pebrine – Louis Pasteur: Nosema bombycis (silkworm)
Example 3. ?-infecting microsporidia of fish and shrimp (horizontal transmission)
Example 3. usually relies on the ? of the host for propagation. These microsporidia may utilise a paratenic (transport) host for transmission such as small crustacea.
Example 1. “Nosema apis” infecting honeybees (horizontal (direct) transmission)
** Chronic infection
Reduced impact to host **
Example 1. does not rely on the death of the host for propagation, however host species suffer reduced fitness and death can result. Many examples including the human-infecting microsporidian
Enterocytozoon bieneusi and Encephalitozoon cuniculi (Pebrine – Louis Pasteur: Nosema bombycis (silkworm)
these 2 genera are imp. in vet medicine!
Example 3. muscle-infecting microsporidia of fish and shrimp (horizontal transmission)
Example 3. usually relies on the death of the host for propagation. These microsporidia may utilise a paratenic (transport) host for transmission such as small crustacea.
Microsporidiosis in dogs and cats is primarily caused by the obligate intracellular parasite ? cuniculi
Medically important species of the genus Encephalitozoon (Encephalitozoon hellem, Encephalitozoon intestinalis and three strains of E. cuniculi) have been described, infecting rabbits, dogs, cats, and birds as well as a wide range of wild, farm, and domestic animals.
Encephalitozoon lacerate and Encephalitozoon pogonae have only been
isolated from ?.
Microsporidiosis in dogs and cats is primarily caused by the obligate intracellular parasite encephalitozoon cuniculi
Medically important species of the genus Encephalitozoon (Encephalitozoon hellem, Encephalitozoon intestinalis and three strains of E. cuniculi) have been described, infecting rabbits, dogs, cats, and birds as well as a wide range of wild, farm, and domestic animals.
Encephalitozoon lacerate and Encephalitozoon pogonae have only been
isolated from reptiles.
Encephalitozoon cuniculi
- In mammals, the most ? and important ? pathogen is E. cuniculi
- E. cuniculi infections have been reported in over ? mammalian species, including humans
- Global distribution - first identified and especially prevalent in domestic ?
- Up to 80% of rabbits in the United States and Europe are serologically positive, which indicates that they have been ? to the organism
- Most remain ? but some infected rabbits develop the disease encephalitozoonosis
- The most common clinical signs associated with this disease involve the ?, ?, and ?
- Neurologic signs can appear rapidly and include ? /?
- Uveitis (inflammation pigmented layer)
- Spores are shed in the ?
- Dogs have a 0-38% prevalence, whilst cats appear to be relatively ?
- But this all depends on the immunostatus of the host and the presence of other diseases
Encephalitozoon cuniculi
- In mammals, the most common and important microsporidian pathogen is E. cuniculi
- E. cuniculi infections have been reported in over 20 mammalian species, including humans
- Global distribution - first identified and especially prevalent in domestic rabbits
- Up to 80% of rabbits in the United States and Europe are serologically positive, which indicates that they have been exposed to the organism
- Most remain asymptomatic but some infected rabbits develop the disease encephalitozoonosis
- The most common clinical signs associated with this disease involve the CNS, eyes, and kidneys
- Neurologic signs can appear rapidly and include head tilt / circling
- Uveitis (inflammation pigmented layer)
- Spores are shed in the urine
- Dogs have a 0-38% prevalence, whilst cats appear to be relatively resistant
- But this all depends on the immunostatus of the host and the presence of other diseases
Evolutionary drift from invertebrates to vertebrates and from aquatic to terrestrial hosts
Phylum: MICROSPORIDIA (Microspora)
➢Obligate ? parasites, ?-forming, infecting every major animal group
➢However, the greatest numbers of described microsporidian species infect arthropods and fish; both considered to be ? (body temperature is variable and dependent on ambient temperature – demonstrates function with temp range)
➢Zoonotic microsporidia are known, but remember they have to overcome two major obstacles, if jumping from poikilotherms (eating infected fish or insects!)
➢more advanced ?
➢Much higher body ?
➢But, true mammalian species do exist of medical and veterinary importance, such as Enterocytozoon bieneusi and Encephalitozoon spp.
(true fungi are facultative parasites (life can be done outside host cell)
➢Microsporidiosis in ? and ? is primarily caused by the obligate intracellular parasite Encephalitozoon cuniculi
➢Originally thought to be basal amitochondriate eukaryotes, now known to be related to ?, as a sister group (secondary loss of mitochondria – relics remain)
➢Ultimate parasites: many have massively ? genome sizes, with the loss of many essential biochemical pathway - no turning back - evolving to become symbionts??
➢Obligate ? ? !! ** ? ** !!
Phylum: MICROSPORIDIA (Microspora)
➢Obligate intracellular parasites, spore-forming, infecting every major animal group
➢However, the greatest numbers of described microsporidian species infect arthropods and fish; both considered to be poikilotherms (body temperature is variable and dependent on ambient temperature – demonstrates function with temp range)
➢Zoonotic microsporidia are known, but remember they have to overcome two major obstacles, if jumping from poikilotherms (eating infected fish or insects!)
➢more advanced immune systems
➢Much higher body temp.
➢But, true mammalian species do exist of medical and veterinary importance, such as Enterocytozoon bieneusi and Encephalitozoon spp.
(true fungi are facultative parasites (life can be done outside host cell)
➢Microsporidiosis in rabbit and dog is primarily caused by the obligate intracellular parasite Encephalitozoon cuniculi
➢Originally thought to be basal amitochondriate eukaryotes, now known to be related to FUNGI, as a sister group (secondary loss of mitochondria – relics remain)
➢Ultimate parasites: many have massively reduced genome sizes, with the loss of many essential biochemical pathway - no turning back - evolving to become symbionts??
➢Obligate Fungal Parasites !! Opportunistic!!
OOMYCETES - the water molds
KNOW ABOUT PYTHIUM!! - come under oomycetes
water mold (pythium) - look like fungi but aren’t!
(Crayfish plague – Aphanomyces astaci)
Pythium insidiosum - Pythiosis
- Pythiosis is an infectious disease caused by a ?-like organism, Pythium ?
- Dogs typically become infected by ingesting or swimming in contaminated ? such as wetlands, ponds, and swamps.
- The infection is typically either ? or ? (dermatitis). Dogs with ? are predisposed to acquiring ? pythiosis in contaminated water.
- Dogs with gastrointestinal pythiosis often have a history of retrieving objects, such as ?, from water and then ? on them
OOMYCETES - the water molds
KNOW ABOUT PYTHIUM!! - come under oomycetes
water mold (pythium) - look like fungi but aren’t!
(Crayfish plague – Aphanomyces astaci)
Pythium insidiosum - Pythiosis
- Pythiosis is an infectious disease caused by a fungus-like organism, Pythium insidiosum
- Dogs typically become infected by ingesting or swimming in contaminated water such as wetlands, ponds, and swamps.
- The infection is typically either GI or cutaneoous (dermatitis). Dogs with open skin wounds are predisposed to acquiring cutaneous pythiosis in contaminated water.
- Dogs with gastrointestinal pythiosis often have a history of retrieving objects, such as sticks, from water and then chewing on them
