309:, which leads to a reduction of the adaptive immune response of the host and eventually leads to an immunocompromised state. Death results from opportunistic infections secondary to disruption of the immune system caused by AIDS. Some viral virulence factors confer ability to replicate during the defensive inflammation responses of the host such as during virus-induced
276:
produced by bacteria that can contaminate human foods. Some of these can remain in "spoiled" food even after cooking and cause illness when the contaminated food is consumed. Other bacterial toxins are chemically altered and inactivated by the heat of
292:
They determine whether infection occurs and how severe the resulting viral disease symptoms are. Viruses often require receptor proteins on host cells to which they specifically bind. Typically, these host cell proteins are
143:. Host-mediated pathogenesis is often important because the host can respond aggressively to infection with the result that host defense mechanisms do damage to host tissues while the infection is being countered (e.g.,
130:
to cause disease is described in terms of the number of infecting bacteria, the route of entry into the body, the effects of host defense mechanisms, and intrinsic characteristics of the bacteria called
190:
Many bacteria must first bind to host cell surfaces. Many bacterial and host molecules that are involved in the adhesion of bacteria to host cells have been identified. Often, the host
246:
Many bacteria produce virulence factors that inhibit the host's immune system defenses. For example, a common bacterial strategy is to produce proteins that bind host antibodies. The
174:. Therefore, strategies to combat certain bacterial infections by targeting these specific virulence factors and mobile genetic elements have been proposed. Bacteria use
240:
into host cells. These virulence factors allow the bacteria to enter host cells and facilitate entry into the body across epithelial tissue layers at the body surface.
505:
840:
198:
lining and of anti-microbial substances around some host cells, it is difficult for certain pathogens to establish direct contact-adhesion.
313:. Many viruses can exist inside a host for long periods during which little damage is done. Extremely virulent strains can eventually
1132:
1128:
1178:
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Many virulence factors are proteins made by bacteria that poison host cells and cause tissue damage. For example, there are many
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833:
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423:
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virulence factors allow it to replicate, modify host defenses, and spread within the host, and they are toxic to the host.
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826:
1337:
115:
111:
1144:
1182:
904:
550:
Thrall, Peter H.; Burdon, Jeremy J. (2003). "Evolution of
Virulence in a Plant Host-Pathogen Metapopulation".
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1015:
381:
1309:
386:
40:
In most, especially in animal systems, virulence refers to the degree of damage caused by a microbe to its
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1273:
1245:
1174:
928:
140:
1323:
999:
401:
391:
232:
Some virulent bacteria produce proteins that either disrupt host cell membranes or stimulate their own
136:
57:
1118:
619:
204:
Some virulent bacteria produce special proteins that allow them to colonize parts of the host body.
150:
The virulence factors of bacteria are typically proteins or other molecules that are synthesized by
1056:
1004:
884:
255:
171:
178:
to synchronise release of the molecules. These are all proximate causes of morbidity in the host.
1102:
972:
950:
919:
894:
877:
624:
167:
1253:
1090:
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systems, often in plants, virulence refers to a pathogen's ability to infect a resistant host.
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981:
889:
853:
632:
349:
191:
818:
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237:
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is able to survive in the acidic environment of the human stomach by producing the enzyme
8:
967:
899:
417:
206:
118:—the evolutionary pressures that lead to virulent traits occurring in a pathogen strain.
20:
563:
1220:
1170:
985:
914:
872:
725:
698:
674:"Plant disease | Importance, Types, Transmission, & Control | Britannica"
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591:
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that are injected into the host cells by specialized secretion apparati, such as the
107:
748:
Flint, S.Jane; Enquist, Lynn W.; Racaniello, Vincent R.; Skalka, Anna Marie (2009).
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989:
943:
938:
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477:
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132:
53:
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45:
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for bacteria are essential proteins for other functions. Due to the presence of
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306:
247:
219:
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144:
41:
1353:
1268:
1235:
1230:
715:
699:"Paradigms of pathogenesis: Targeting the mobile genetic elements of disease"
579:
433:
159:
110:
induced by a parasite upon its host. Virulence can be understood in terms of
34:
571:
1110:
994:
734:
587:
491:
472:
260:
1304:
1158:
1031:
1021:
364:
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233:
613:
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and the bound virus then enters the host cell. Virulent viruses such as
1106:
1098:
1064:
1026:
933:
155:
114:—those specific traits of the pathogen that help make the host ill—and
506:"MeSH - Medical Subject Headings, Karolinska Institute, 13 April 2010"
1166:
314:
81:
1200:
357:
345:
302:
214:. Colonization of the stomach lining by this bacterium can lead to
127:
30:
1205:
163:
103:
49:
326:
211:
151:
848:
456:"Q and A: What is a pathogen? A question that begs the point"
404: – Disproved hypothesis of epidemiologist Theobald Smith
310:
286:
273:
195:
71:
747:
95:, meaning "a poisoned wound" or "full of poison." The term
64:
226:
tends to correlate with the level of production of urease.
181:
305:, have mechanisms for evading host defenses. HIV infects
298:
750:
Principles of
Virology. Vol. II Pathogenesis and Control
752:(3rd ed.). Washington, D.C.: ASM. pp. 42–7.
321:
within the virus population inside a host. The term "
612:
611:
453:
1351:
703:Frontiers in Cellular and Infection Microbiology
367:of virulent bacteriophages is contrasted by the
772:
741:
530:
834:
799:"lytic phage | virus | Britannica"
549:
447:
154:. These proteins are coded for by genes in
75:
841:
827:
724:
714:
481:
471:
420: – Theory by biologist Paul W. Ewald
16:Severity of disease pathogens on its host
1133:Preventable fraction among the unexposed
1129:Attributable fraction for the population
773:Madigan, M. T.; Martinko, J. M. (2006).
607:
605:
1137:Preventable fraction for the population
1125:Attributable fraction among the exposed
182:Methods by which bacteria cause disease
135:. Many virulence factors are so-called
1352:
645:
263:of the bacterium by host immune cells.
222:. The virulence of various strains of
37:'s ability to cause damage to a host.
822:
766:
602:
106:standpoint, virulence is the loss of
87:, meaning disease severity. The word
1300:Correlation does not imply causation
1216:Animal testing on non-human primates
696:
646:Lewis, Charlton T.; Short, Charles.
633:participating institution membership
424:Verotoxin-producing Escherichia coli
121:
48:of an organism—its ability to cause
281:
13:
454:Pirofski LA, Casadevall A (2012).
14:
1371:
531:Biology Online (7 October 2019).
777:(11th ed.). Prentice Hall.
99:does not only apply to viruses.
791:
775:Brock Biology of Microorganisms
1183:Pre- and post-test probability
905:Patient and public involvement
690:
666:
639:
543:
524:
498:
325:" is used for viruses such as
19:For the academic journal, see
1:
440:
371:of temperate bacteriophages.
56:. In the specific context of
1310:Sex as a biological variable
387:Membrane vesicle trafficking
344:of virulent viruses include
91:derives from the Latin word
7:
1274:Intention-to-treat analysis
1246:Analysis of clinical trials
1175:Specificity and sensitivity
929:Randomized controlled trial
374:
141:type three secretion system
10:
1376:
402:Law of declining virulence
392:Bacterial effector protein
243:Immune response inhibitors
166:. Certain bacteria employ
18:
1318:
1283:Interpretation of results
1282:
1244:
1193:
1143:
1117:
1079:
1049:
1040:
1016:Nested case–control study
966:
913:
860:
620:Oxford English Dictionary
382:Host–pathogen interaction
337:and cause disease there.
885:Academic clinical trials
716:10.3389/fcimb.2012.00161
356:and a number of related
256:Streptococcus pneumoniae
172:horizontal gene transfer
1103:Relative risk reduction
951:Adaptive clinical trial
895:Evidence-based medicine
878:Adaptive clinical trial
625:Oxford University Press
572:10.1126/science.1080070
168:mobile genetic elements
1091:Number needed to treat
473:10.1186/1741-7007-10-6
192:cell surface receptors
76:
52:—is determined by its
1095:Number needed to harm
982:Cross-sectional study
934:Scientific experiment
890:Clinical study design
350:T-even bacteriophages
333:which can invade the
1061:Cumulative incidence
697:Keen, E. C. (2012).
340:Extensively studied
968:Observational study
900:Real world evidence
854:experimental design
623:(Online ed.).
564:2003Sci...299.1735T
418:Theory of virulence
369:temperate lifecycle
224:Helicobacter pylori
207:Helicobacter pylori
80:) derives from the
21:Virulence (journal)
1360:Microbiology terms
1254:Risk–benefit ratio
1221:First-in-man study
1171:Case fatality rate
1012:Case–control study
986:Longitudinal study
803:www.britannica.com
678:www.britannica.com
653:A Latin Dictionary
397:Infectious disease
1347:
1346:
1295:Survivorship bias
1259:Systematic review
1226:Multicenter trial
1189:
1188:
1179:Likelihood-ratios
1151:Clinical endpoint
1119:Population impact
1073:Period prevalence
850:Clinical research
784:978-0-13-144329-7
759:978-1-55581-480-9
631:(Subscription or
408:Optimal virulence
319:natural selection
137:effector proteins
133:virulence factors
122:Virulent bacteria
54:virulence factors
1367:
1194:Trial/test types
1069:Point prevalence
1047:
1046:
990:Ecological study
973:EBM II-2 to II-3
944:Open-label trial
939:Blind experiment
915:Controlled study
843:
836:
829:
820:
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813:
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558:(5613): 1735–7.
547:
541:
540:
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522:
521:
519:
517:
508:. Archived from
502:
496:
495:
485:
475:
451:
429:Virulence factor
365:lytic life cycle
354:Escherichia coli
317:by mutation and
282:Virulent viruses
238:macropinocytosis
112:proximate causes
79:
1375:
1374:
1370:
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1364:
1350:
1349:
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1240:
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1087:Risk difference
1075:
1036:
970:
962:
917:
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873:Trial protocols
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847:
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797:
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512:on 3 March 2016
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503:
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342:model organisms
301:, which causes
284:
184:
126:The ability of
124:
116:ultimate causes
24:
17:
12:
11:
5:
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1344:
1342:
1341:
1338:List of topics
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1290:Selection bias
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1218:
1213:
1211:Animal testing
1208:
1203:
1197:
1195:
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1190:
1187:
1186:
1163:Mortality rate
1149:
1147:
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1123:
1121:
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1055:
1053:
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1038:
1037:
1035:
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1024:
1019:
1009:
1008:
1007:
1002:
992:
978:
976:
964:
963:
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956:Platform trial
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868:Clinical trial
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838:
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823:
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537:Biology Online
523:
497:
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426:
421:
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413:Super-spreader
410:
405:
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394:
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384:
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373:
335:nervous system
331:herpes simplex
307:T-helper cells
283:
280:
279:
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271:food poisoning
267:
264:
248:polysaccharide
244:
241:
230:
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216:gastric ulcers
202:
199:
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176:quorum sensing
145:cytokine storm
123:
120:
15:
9:
6:
4:
3:
2:
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1269:Meta-analysis
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1236:Vaccine trial
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1231:Seeding trial
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1000:Retrospective
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921:
920:EBM I to II-1
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434:Antivirulence
432:
430:
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372:
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366:
361:
359:
355:
352:which infect
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324:
323:neurovirulent
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160:bacteriophage
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119:
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109:
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83:
78:
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69:
66:
61:
59:
58:gene for gene
55:
51:
47:
46:pathogenicity
43:
38:
36:
35:microorganism
32:
28:
22:
1336:
1329:
1322:
1154:
1111:Hazard ratio
995:Cohort study
806:. Retrieved
802:
793:
774:
768:
749:
743:
706:
702:
692:
681:. Retrieved
677:
668:
657:. Retrieved
652:
648:"vÄ«rĹlentus"
641:
618:
555:
551:
545:
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526:
514:. Retrieved
510:the original
500:
463:
459:
449:
362:
339:
291:
285:
261:phagocytosis
254:
223:
205:
201:Colonization
149:
125:
101:
96:
92:
88:
84:
67:
62:
39:
26:
25:
1305:Null result
1264:Replication
1159:Infectivity
1081:Association
1032:Case report
1022:Case series
1005:Prospective
533:"Virulence"
460:BMC Biology
295:endocytosed
234:endocytosis
156:chromosomal
1107:Odds ratio
1099:Risk ratio
1065:Prevalence
1051:Occurrence
1027:Case study
808:2023-01-02
683:2023-01-02
659:2023-01-02
635:required.)
614:"virulent"
441:References
348:and other
104:ecological
93:virulentus
77:virulentia
1167:Morbidity
1155:Virulence
1057:Incidence
580:0036-8075
259:inhibits
97:virulence
82:adjective
68:virulence
27:Virulence
1354:Category
1331:Glossary
1324:Category
1201:In vitro
1042:Measures
861:Overview
735:23248780
588:12637745
516:13 April
492:22293325
375:See also
358:bacteria
346:virus T4
277:cooking.
229:Invasion
187:Adhesion
164:plasmids
128:bacteria
102:From an
89:virulent
85:virulent
31:pathogen
1206:In vivo
726:3522046
709:: 161.
596:6894315
560:Bibcode
552:Science
483:3269390
251:capsule
162:DNA or
152:enzymes
108:fitness
50:disease
781:
756:
733:
723:
594:
586:
578:
490:
480:
327:rabies
315:evolve
274:toxins
266:Toxins
220:cancer
212:urease
44:. The
33:'s or
1145:Other
629:
592:S2CID
466:: 6.
311:fever
287:Virus
196:mucus
158:DNA,
74:noun
72:Latin
29:is a
984:vs.
852:and
779:ISBN
754:ISBN
731:PMID
584:PMID
576:ISSN
518:2010
488:PMID
363:The
329:and
303:AIDS
218:and
170:and
65:noun
63:The
42:host
721:PMC
711:doi
568:doi
556:299
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468:doi
299:HIV
253:of
236:or
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