Table 1.

Types of infections that produce pain, itch, or analgesia.

Pathogen name	Sensation	Infection site(s)	Neuronal sensitization/silencing mechanism(s)
Bacteria
Citrobacter rodentium	Pain	GI tract	Suppression of I(A) currents
Clostridium difficile	Pain	GI tract	Unknown
Escherichia coli	Pain	GI tract, genitourinary tract	LPS activates TLR4 and TRPA1
Salmonella enterica	Pain	GI tract	LPS and flagellin activate TLRs and/or TRPA1
Helicobacter pylori	Pain	GI tract	Unknown
Porphymonas gingivalis	Pain	Oral cavity	LPS sensitizes TRPV1
Streptococcus mutans	Pain	Oral cavity	Unknown
Staphylococcus aureus	Pain, Itch	Skin, soft tissues	α-toxin, formyl peptides
Streptococcus pyogenes	Pain	Skin, pharynx	Unknown
Listeria monocytogenes	Pain	CNS, meninges, GI tract	Unknown
Streptococcus pneumoniae	Pain	CNS, meninges, lung	Unknown
Viruses
Herpes simplex virus	Pain	DRG/trigeminal ganglia	Nociceptor sensitization
Herpes zoster virus	Pain	DRG/trigeminal ganglia	Post-herpetic neuralgia
Influenza virus	Pain	Respiratory tract	IDO-mediated sensitivity
Norovirus	Pain	GI tract	Unknown
Rotavirus	Pain	GI tract	Unknown
Fungi
Candida albicans	Pain, Itch	Skin, genito-urinary tract	Zymosan sensitizes nociceptor neurons
Tinea cruris	Itch	Groin (jock itch)	Unknown
Tinea pedis	Itch	Feet (athlete’s foot)	Unknown
Parasites
Hookworms	Itch	Skin, GI tract	Unknown
Onchocerca volvulus	Itch	Skin, eyes	Unknown
Pinworms	Itch	Skin, GI tract, anus	Unknown
Schistosoma	Itch	Skin (swimmer’s itch)	Unknown
Pathogens that block pain
Clostridium botulinum	Painless	Skin, GI tract	BoNTs block neurotransmission
Clostridium tetani	Painless	Skin	TeNT blocks neurotransmission
Mycobacterium ulcerans	Painless	Skin	Mycolactone induces hyperpolarization
Mycobacterium leprae	Painless	Skin	Schwann cell destruction
Treponema pallidum	Painless	Skin, genitourinary tract	Unknown