Table 1

Pathogens and their classification

PathogensCategoryCausative agentVectorSome popular virulence factor
Plague (Yersinia pestis)ABacteriumRodent fleaEndotoxin—lipopolysaccharide (LPS), lipid A with poor Toll-like receptor 4 (TLR4)
Smallpox (Variola major)AVirusInfected humanEndotoxin—SPICE, CKBP-II
Botulism (clostridium botulinum)ABacteriatoxin, bacteria sporeExotoxin—neurotoxin
Anthrax (Bacillus anthracis)ABacteriaInfected animalExotoxin—capsule, lethal toxin, and edema toxin
Tularaemia (Francisella tularensis)ABacteriaSkin contact, tick, contaminated water or aerosols, lab exposure, deer fly bitesUnknown, but proteins such as MglA, IglC, AcpA and MinD have been implicated.
Viral haemorrhagic fever
Filovirus (Ebola) and
Arenavirus (Lassa virus)
AVirusInfected animal—Ebola, multimammate rat—Lassa virusEbola: adherence factor (glycoprotein), VP35
Lassa: Glocoprotein, nucleoprotein
Brucellosis (Brucella species)BBacteriaInfected animalEndotoxin—LPS, T4SS secretion and BvrR/BvrS.
Glanders (Burkholderia mallei)BBacteriaaffected animals(eg, horses)Quorum sensing, adhesion, capsular polysaccharide, actin-based motility, LPS
melioidosis (Burkholderia pseudomallei)BBacteriaContaminated waterEndotoxin—LPS
Psittacosis (Chlamydia psittaci)BBacteriaContact with infected birdsUnknown
Q Fever (Coxiella burnetti)BBacteriaContact with animal faeces, milk, productsEndotoxin—LPS
Ricin toxin (Ricinus communis)BPoison, warfare agentCastor beansToxin
Epsilon toxin (clostridium perfringens)BBacteriaRaw meat and poultryAlpha toxin, kappa toxin
SalmonellaBBacteriaFoodInvasion factors—type III secretion systems, T3SS1 and T3SS2
Typhus fever (Rickettsia prowazekii)BBacteriafleas, lice, chiggersT4SS secretion, Phospholipase A2
Staphylococcal enterotoxin BBBacteriaFood poisoningTSST-1
Vibrio choleraBBacteriaContaminated food or waterCholera toxin
Eastern equine encephalitis—AlphavirusesBVirusInfected mosquitoGlocoprotein
Nipah virusCVirusInfected animals (bats, pigs) and infected humans.V and C proteins
HantavirusCVirusRodents urine, faeces, salivaSurface glycoproteins G1 and G2, G1 protein