Flacherie (literally: "flaccidness") is a disease of
silkworms, caused by silkworms eating infected or contaminated
mulberry leaves. Flacherie infected silkworms look weak and can die from this disease. Silkworm larvae that are about to die from Flacherie are a dark brown.
There are two kinds of flacherie: essentially, infectious (viral) flacherie and noninfectious (''touffée'') flacherie. Both are technically a lethal
diarrhea
Diarrhea, also spelled diarrhoea, is the condition of having at least three loose, liquid, or watery bowel movements each day. It often lasts for a few days and can result in dehydration due to fluid loss. Signs of dehydration often begin w ...
.
Touffée flacherie is caused by
heat wave
A heat wave, or heatwave, is a period of excessively hot weather, which may be accompanied by high humidity, especially in oceanic climate countries. While definitions vary, a heat wave is usually measured relative to the usual climate in the ...
s.
Viral flacherie is ultimately caused by infection with
''Bombyx mori'' infectious flacherie virus (BmIFV,
Iflaviridae
''Iflaviridae'' is a family of positive sense RNA viruses insect-infecting viruses. Some of the insects commonly infected by iflaviruses include aphids, leafhoppers, flies, bees, ants, silkworms and wasps. The name "Ifla" is derived from the n ...
),
''Bombyx mori'' densovirus (BmDNV,
Parvoviridae
Parvoviruses are a family of animal viruses that constitute the family ''Parvoviridae''. They have linear, single-stranded DNA (ssDNA) genomes that typically contain two genes encoding for a replication initiator protein, called NS1, and the pr ...
) or
''Bombyx mori'' cypovirus 1 (BmCPV-1,
Reoviridae
''Reoviridae'' is a family of double-stranded RNA viruses. Member viruses have a wide host range, including vertebrates, invertebrates, plants, protists and fungi. They lack lipid envelopes and package their segmented genome within multi-layere ...
). This either alone or in combination with
bacteria
Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of prokaryotic microorganisms. Typically a few micrometr ...
l infection destroys the
gut tissue. Bacterial
pathogen
In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ ...
s contributing to infectious flaccherie are ''
Serratia marcescens
''Serratia marcescens'' () is a species of rod-shaped, Gram-negative bacteria in the family Yersiniaceae. It is a facultative anaerobe and an opportunistic pathogen in humans. It was discovered in 1819 by Bartolomeo Bizio in Padua, Italy.Serra ...
'', and species of ''
Streptococcus
''Streptococcus'' is a genus of gram-positive ' (plural ) or spherical bacteria that belongs to the family Streptococcaceae, within the order Lactobacillales (lactic acid bacteria), in the phylum Bacillota. Cell division in streptococci occurs ...
'' and ''
Staphylococcus'' in the form known as ''thatte roga''.
In the nineteenth century, flacherie resisted the efforts of
Louis Pasteur.
[G. Balbiani, ''Leçons sus les sporozoaires'', Paris, 1884, p. 160-163 and 167-168]
online
References
Insect viral diseases
Diseases of Lepidopterans
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