Introduction to Veterinary Mycology

Mycology derived from aGreek word (Gr mykes - mushrooms +

logos -discourse), etymologicaly, is the study of mushrooms. Mush
rooms are among the largest of fungi and attracted the attention of
naturalists before microscope or even simple lenses had been thought
of. With the invention of the microscope by Leeuwenhoek in the
seventeenth century the systemic study of fungi began, and the man
who deserves the honour of being called the founder of the science of
mycology is Pier Antonio Micheli, the talian botanist who, in 1729,
published Nova Plantarum genera in which his researches on fungi
were included.
Veterinary mycology as abranch of Veterinary Science may be
considered to date from the first half of the nineteenth century whenthe
ability of fungi to cause diseases in plants,animals and man was first
established.in 1807 in France Benedict Prevost (1755-1819), a gentle
man of independent means, published the results of the experiments
which proved that wheat buntwas caused by the smut fungus Tilletia
caries. In the same yeari. e.1835, in' taly; Agostinobassi (1773-1856),
a lawyerturned farmer, began a lengthy experimental study by which he
demonstratedthat muscardine disease of silkworms was caused bythe
fungus known as Beauveria bassiana. Shortly after the publication of
Bassi's classical monograph in 1835-1836 two medical men, J. L.
Schoenlein(1793-1864) in Zurich andDavid Gruby(1810-98) in Paris,
showed that the different types of human ringworm were mycotic
infections. Theystudied the fungus ofscalp infectionfavus (Trichophyton
schoenlein) in 1839, and in the same year Lagenbeck described the
Berg
yeast like organisms of Thrush (Candida albicans). In1842 F.T. that
(1806-87) of Stockholm and Gruby announced, independently,
Remak had
thrush was caused by afungus (Candida albicans). Roberteven isolated
described favus earlier, but his work wasignored: Gruby
inoculating a healthy
the fungus of favuS and produced the disease byKoch formulated them.
subject, thus fulfilling Koch's postulates before
its earlier beginnings, veterinary and medicdl mycology
Inspite of
was soon overshadowed because of the development of bacteriology
the mid-nineteenth century
and recognition of bacterial pathogensofinthe century, though some of
and the discovery of viruses at the turn
 the fungal diseases (dermatophytoses) are among the more
infections of man and animals. This is perhapS attributablecommon to the
relatively benign nature of the common mycOses, the rarity of the more
serious ones, and the difficulty of differentiation of these structurally
Complex forms.
The first major revival of interest in medical mycology is
with the studies of ringworm by the French dermatologistassociated
Raimond
Sabouraud (1864-1938). The publication of the classic work on der
matophyte infections 'Les Teignes' is a model of scientific observation.
Sabouraud'swork demonstrated and confirmed that the same dermato
phytes attack domestic animals and men emphasizing the
of the animal reservoir of infection in the importance
epidemiology of human
ringworm. During the same period French Veterinarians were showing
deep interest both in ringworm and other mycotic diseases and obser
vations were made in two monographs on aspergillosis published in
1897 by L. Renon and A. Lucet respectively. Another
which attracted continuous attention at that timesystemic disease
was epizootic.
lymphangitis of horses and mules and a monograph waswritten on the
disease by Pallin in 1904. Some true fungus infections
and coccidioidomycosis) were first described as caused (histoplasmosis
by protozoan
parasites, but the works of Ophuls, Brumpt, Gilchristand Smith (most
of them dermatologists) dilineated their true nature and the
their epidemiology. These studies have revealed new and economi extent of
cally important mycses attacking a high proportion of the local
populationof both domestic and farm animals.
During the recentdays mycologists have accepted greater respon
sibilities for the study of fungi of medical importance, and physicians
have learned that mycoses are more frequent causes of morbidity and
mortality than had been recognised previously. Together they have
given more attentionto the mycoses in differential diagnosis of disease,
studied clinical variability in the mycoses,improved methods of detect
ing and identifying fungi found in tissue sections and emphasized the
necessity for isolation of fungi in culture. Collaboration between physi
Cian and mycologist has been placed upon a more substantial basis,to
the benefit of both the sciences.
Today we recognise some 200 'pathogens' amnong the approxi
mately 100,000 species offungi. About 20 of these may cause systemic
intections, about 20 are regularly isolated from cutaneous infections and
adozen are associated with severe, localized,subcutaneous diseases.
In addition,there is a long list of opportunistic organisms that may cause
diseases in the debilitated patients.
2
 In addition to pathogenicity, fungi affect animals and man by two
other ways. They can act as poisons and allergens. Larger tung
poisonous for man have been known throughout historic times and the
poisonoUs effect of ergot of rye has been recorded since the Middle
Ages. Ergot poisoning is the oldest example of what are known
"mycotoxicoses", that is the poisoning due to the consumption of food
or feed contaminated by toxin producing microfungi. Two notorious
examples of mycotoxicoses only recently elucidated are facial eczema
of sheep in New Zealand and elsewhere caused by the ingestion of
spores of Pthomyces chartarumwhich occur in quantity on grass under
certain climatic conditions and aflatoxicosis due to series of related
toxins produced in groundnuts (peanuts) and other plant products by
strains of Aspergillus flavus. Very small doses of aflatoxin are fatal to
youngducklings and turkeys and long term ingestion may contribute to
the development of cancer of the liver in man. More is known about
fungal allergy in agricultural workers than in farm animals.
Inconclusion, perhaps the only generalization that need be drawn
possible
is that the implication of fungi should never be forgotten as a
solution to the problem of a disease of uncertain aetiology