Flacherie is a disease of silkworms, caused by silkworms eating infected or contaminated mulberry

Mulberry

Morus is a genus of flowering plants in the family Moraceae. The 10–16 species of deciduous trees it contains are commonly known as Mulberries....

 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 (or three) kinds of flacherie: basically, infectious (viral) flacherie and noninfectious (touffee) flacherie. Both are technically a lethal diarrhea

Diarrhea

Diarrhea , also spelled diarrhoea, is the condition of having three or more loose or liquid bowel movements per day. It is a common cause of death in developing countries and the second most common cause of infant deaths worldwide. The loss of fluids through diarrhea can cause dehydration and...

.

Touffee flacherie is caused by heatwaves (touffee means "sudden heat spell" in French).

Viral flacherie is ultimately caused by infection with Bombyx mori infectious flacherie virus (BmIFV, Dicistroviridae

Dicistroviridae

The Dicistroviridae are a family of Group IV insect-infecting viruses. Some of the insects commonly infected by dicistroviruses include aphids, leafhoppers, flies, bees, ants, silkworms.-Taxonomy:...

), Bombyx mori densovirus (BmDNV, Parvoviridae

Parvoviridae

The Parvoviridae family includes the smallest known viruses, and some of the most environmentally resistant. They were discovered during the 1960s and affect vertebrates and insects...

) or Bombyx mori cypovirus 1 (BmCPV-1, Reoviridae

Reoviridae

Reoviridae is a family of viruses that can affect the gastrointestinal system and respiratory tract. Viruses in the family Reoviridae have genomes consisting of segmented, double-stranded RNA...

). This either alone or in combination with bacteria

Bacteria

Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...

l infection destroys the gut

Gut (zoology)

In zoology, the gut, also known as the alimentary canal or alimentary tract, is a tube by which bilaterian animals transfer food to the digestion organs. In large bilaterians the gut generally also has an exit, the anus, by which the animal disposes of solid wastes...

 tissue. Bacterial pathogen

Pathogen

A pathogen gignomai "I give birth to") or infectious agent — colloquially, a germ — is a microbe or microorganism such as a virus, bacterium, prion, or fungus that causes disease in its animal or plant host...

s contributing to infectious flaccherie are Serratia marcescens

Serratia marcescens

Serratia marcescens is a species of Gram-negative, rod-shaped bacterium in the family Enterobacteriaceae. A human pathogen, S. marcescens is involved in nosocomial infections, particularly catheter-associated bacteremia, urinary tract infections and wound infections, and is responsible for 1.4% of...

, and species of Streptococcus

Streptococcus

Streptococcus is a genus of spherical Gram-positive bacteria belonging to the phylum Firmicutes and the lactic acid bacteria group. Cellular division occurs along a single axis in these bacteria, and thus they grow in chains or pairs, hence the name — from Greek στρεπτος streptos, meaning...

and Staphylococcus

Staphylococcus

Staphylococcus is a genus of Gram-positive bacteria. Under the microscope they appear round , and form in grape-like clusters....

in the form known as thatte roga.

Louis Pasteur

Louis Pasteur

Louis Pasteur was a French chemist and microbiologist born in Dole. He is remembered for his remarkable breakthroughs in the causes and preventions of diseases. His discoveries reduced mortality from puerperal fever, and he created the first vaccine for rabies and anthrax. His experiments...

, who began his studies on silkworms diseases in 1865, was the first one able to recognize that mortality due to viral flacherie was caused by infection

Infection

An infection is the colonization of a host organism by parasite species. Infecting parasites seek to use the host's resources to reproduce, often resulting in disease...

. (Priority, however, was claimed by Antoine Béchamp

Antoine Béchamp

Pierre Jacques Antoine Béchamp was a French biologist. He studied silkworm parasites, and was the first to synthesise Atoxyl.-Biography:...

.)