Research and analysis

NOIDs causative agents: week 52 (week ending 28 December 2025)

Updated 31 December 2025

The list of causative agents that laboratories must notify the UK Health Security Agency (UKHSA) about has been expanded to include additional notifiable organisms. These became reportable under the Health Protection (Notification) (Amendment) Regulations from 6 April 2025.

Publication of the additional causative agents will begin at a later date, once reporting development work has been undertaken to include them.

This report contains statistics of formal notifications of causative agent test results to UKHSA from diagnostic laboratories in England, under Regulation 4 of the Health Protection (Notifications) Regulations 2010.

The number of notifications in this report reflects test results provided from laboratories to UKHSA before UKHSA interprets or applies standardised case definitions to these test results. Individual test results will not always result in a confirmed diagnosis of a disease, therefore the notifications in this report should not be considered counts of cases and should be interpreted with caution.

Epidemiology reports including confirmed case numbers using standardised case definitions are published separately on a per pathogen or pathogen-group basis.

Laboratories in England have a statutory duty to notify UKHSA of the identification of the following causative agents:

  • Bacillus anthracis
  • Bacillus cereus
  • Bordetella pertussis
  • Borrelia spp
  • Brucella spp
  • Burkholderia mallei
  • Burkholderia pseudomallei
  • Campylobacter spp
  • Carbapenemase-producing Gram-negative bacteria
  • Chikungunya virus
  • Chlamydophila psittaci
  • Clostridium botulinum
  • Clostridium perfringens
  • Clostridium tetani
  • Corynebacterium diphtheriae
  • Corynebacterium ulcerans
  • Coxiella burnetii
  • Crimean-Congo haemorrhagic fever virus
  • Cryptosporidium spp
  • Dengue virus
  • Ebola virus
  • Entamoeba histolytica
  • Escherichia coli O 157
  • Francisella tularensis
  • Giardia spp
  • Guanarito virus
  • Haemophilus influenzae (invasive)
  • Hanta virus
  • hepatitis A
  • hepatitis B
  • hepatitis C
  • hepatitis D
  • hepatitis E
  • influenza virus
  • Junin virus
  • Kyasanur Forest disease virus
  • Lassa virus
  • Legionella spp
  • Leptospira interrogans
  • Listeria monocytogenes
  • Machupo virus
  • Marburg virus
  • measles virus
  • mpox virus
  • mumps virus
  • Mycobacterium tuberculosis complex
  • Neisseria meningitidis
  • Omsk haemorrhagic fever virus
  • Plasmodium falciparum
  • Plasmodium Knowlesi
  • Plasmodium Malariae
  • Plasmodium Ovale
  • Plasmodium Vivax
  • polio virus
  • Rabies virus
  • Rickettsia spp
  • Rift Valley fever virus
  • Rubella virus
  • Sabia virus
  • Salmonella spp
  • SARS coronavirus
  • Shigella spp
  • Streptococcus group A (invasive)
  • Streptococcus pneumoniae (invasive)
  • Varicella zoster virus
  • Variola virus
  • Vibrio cholerae
  • West Nile virus
  • Yellow fever virus
  • Yersinia pestis

Statutory notifications of causative agents, grouped by root organism

Totals for the current week compared to the previous 5.

Week notification received 2025/47 2025/48 2025/49 2025/50 2025/51 2025/52
Arboviruses            
West Nile Virus - - - - 1 1
Bacillus            
Bacillus cereus 23 21 22 20 15 17
Bordetella            
Bordetella pertussis 1 3 6 4 2 2
Borrelia            
Borrelia burgdorferi 23 40 22 32 26 19
Borrelia other named 1 - - - - -
Borrelia sp 5 4 6 4 4 8
Brucella            
Brucella sp 3 2 1 2 3 1
Burkholderia            
Burkholderia mallei - - - - - 1
Campylobacter            
Campylobacter coli 28 25 19 16 20 10
Campylobacter fetus 1 4 - - - 1
Campylobacter jejuni 278 223 279 294 279 214
Campylobacter other named 1 1 1 2 - 3
Campylobacter rectus 1 1 - - - -
Campylobacter sp 879 955 824 891 847 662
Campylobacter upsaliensis 1 - 1 - 1 1
Campylobacter ureolyticus (bacteroides corrodens) - 1 1 1 1 1
Chikungunya virus            
Chikungunya virus - 1 1 2 2 -
Clostridium            
Clostridium perfringens 41 58 38 32 30 51
Coronavirus            
Coronavirus 27 33 54 77 95 95
Human coronavirus 229e - 5 3 5 - 2
Human coronavirus hku1 - - - 1 - -
Human coronavirus nl63 - - - 3 - 1
Human coronavirus oc43 1 1 - 2 1 5
SARS-CoV-2 antibody void 6 - - - - 2
SARS-CoV-2 coronavirus (COVID-19) 638 765 791 1,351 624 544
SARS-CoV-2 coronavirus (COVID-19) indeterminate 24 28 71 50 34 10
SARS-CoV-2 IgG antibody negative 5 2 6 10 7 4
SARS-CoV-2 IgG antibody positive 48 49 50 77 38 26
SARS-CoV-2 total antibody negative 4 8 8 - - 12
SARS-CoV-2 total antibody positive 15 37 19 19 7 43
Corynebacterium            
Corynebacterium diphtheriae 2 2 4 6 5 3
Corynebacterium ulcerans - - - 1 1 -
Coxiella            
Coxiella burnetii - - 1 1 - -
Cryptosporidium            
Cryptosporidium cuniculus 2 1 - - - -
Cryptosporidium hominis 8 2 6 10 11 3
Cryptosporidium meleagridis 2 - - - - -
Cryptosporidium parvum 29 20 34 36 33 13
Cryptosporidium sp 42 58 50 37 28 34
Cryptosporidium ubiquitum - 1 - - - -
Entamoeba            
Entamoeba histolytica 4 2 5 4 4 3
Escherichia            
Escherichia coli O 157 11 13 11 4 5 3
Flaviviruses            
Dengue virus 4 6 3 3 3 4
Giardia            
Giardia intestinalis - - - - 1 1
Giardia sp 143 124 145 124 148 84
Haemophilus            
Haemophilus influenzae 46 80 68 62 71 53
Hepatitis viruses            
Hepatitis A 17 35 12 14 12 13
Hepatitis B 243 239 271 253 255 159
Hepatitis C 232 213 269 232 588 148
Hepatitis D 3 4 6 5 4 2
Hepatitis E 21 39 26 33 31 24
Influenza virus            
Influenza A 3,871 7,007 9,224 9,518 7,845 6,020
Influenza B 57 73 46 71 51 47
Influenza indeterminate 15 9 12 18 6 21
Influenza ungrouped 88 148 219 218 318 228
Legionella            
Legionella longbeachae - - 1 - - -
Legionella pneumophila 5 4 2 7 12 4
Legionella sp 7 4 4 6 3 -
Listeria            
Listeria monocytogenes 10 4 3 7 2 6
Mycobacterium            
Mycobacterium tuberculosis 103 94 97 88 101 68
Neisseria            
Neisseria meningitidis 35 27 40 40 25 28
Orthopoxvirus            
Mpox virus positive 19 12 12 6 8 2
Paramyxoviruses            
Measles virus 7 25 11 11 9 8
Mumps virus 4 2 5 8 5 3
Plasmodium            
Plasmodium falciparum 3 14 - - - -
Plasmodium malariae - 2 - - - -
Plasmodium ovale - 3 - - - -
Plasmodium vivax - 2 - - - -
Polyomavirus            
Polyomavirus BK 49 71 73 75 79 53
Polyomavirus JC 14 7 2 18 7 15
Polyomavirus untyped 16 12 10 13 14 9
Rickettsia            
Rickettsia prowazekii - 1 - - - -
Rickettsia rickettsii - 1 - - - -
Rickettsia spotted fever - - 1 - 1 1
Rickettsia tsutsugamushi - - - 1 - 1
Rubella virus            
Rubella virus 1 1 1 1 2 2
Salmonella            
Other salmonellas 65 53 64 48 25 15
Salmonella agona - - 5 - - -
Salmonella bareilly 7 6 - 7 - -
Salmonella chester 5 - - - - -
Salmonella enterica - 5 - - 5 -
Salmonella enteritidis 71 62 56 32 22 8
Salmonella infantis 6 - - - - -
Salmonella kentucky - 6 - - - -
Salmonella newport 13 6 - - - -
Salmonella saint-paul - 8 - - - -
Salmonella sp 35 39 24 57 102 88
Salmonella stanley - 5 - - - -
Salmonella typhi and paratyphi 13 14 10 11 7 -
Salmonella typhimurium 23 22 22 23 12 9
Shigella            
Shigella boydii 2 1 1 1 1 2
Shigella dysenteriae 1 - 2 1 - -
Shigella flexneri 21 19 12 27 9 8
Shigella sonnei 35 46 35 27 39 11
Shigella sp 63 59 52 42 41 38
Streptococcus            
Streptococcus group A 57 43 58 55 48 56
Streptococcus pneumoniae 101 105 151 143 189 160
Vibrio            
Vibrio cholerae - 1 4 - - -

Carbapenemase-producing Enterobacterales (CPE)

For all Carbapenemase-producing Gram-negative organisms, the reports are de-duplicated by first mention of organism species and resistance mechanism by person in a rolling 52-week period.

Note: the numbers presented here do not include specimens that have been referred to the Antimicrobial Resistance and Healthcare Associated Infections (AMRHAI).

Week notification received 2025/47 2025/48 2025/49 2025/50 2025/51 2025/52
Citrobacter              
Citrobacter spp KPC 1 1 - 1 - -
  NDM 5 1 - 2 2 -
  OXA48 3 - 4 2 - -
  Other 1 - - 1 - -
Enterobacter              
Enterobacter cloacae complex IMP 5 2 - 3 - -
  KPC 4 4 5 4 4 -
  NDM 11 7 6 4 14 2
  OXA48 2 5 8 6 4 4
  VIM - - - - 1 -
  Other 3 1 1 - 1 -
Other enterobacter spp NDM - - - - 1 -
  OXA48 1 - - - - -
Escherichia              
Escherichia coli IMP - - 1 - - -
  KPC 4 4 4 3 2 1
  NDM 15 12 25 14 12 6
  OXA48 32 26 28 21 19 4
  VIM 1 - 1 - - -
  Other 3 3 3 1 1 -
Escherichia marmotae NDM - - - - 1 -
  Other - - - - 1 -
Klebsiella              
Klebsiella aerogenes NDM - - - - 1 -
  OXA48 - - 2 - 1 -
Klebsiella oxytoca IMP - - - - - 1
  KPC 1 1 1 3 - -
  NDM - 1 - - - -
  OXA48 1 - 2 1 - -
  VIM - 1 - - - -
  Other - 1 1 - - -
Klebsiella pneumoniae IMP 1 - 2 1 - -
  KPC 12 15 12 5 1 1
  NDM 10 10 7 4 8 1
  OXA48 14 13 10 15 13 2
  VIM - - 1 1 - -
  Other 1 1 3 1 2 -
Klebsiella pneumoniae subsp ozenae KPC - 1 - - - -
Klebsiella variicola KPC - 1 - - - -
Leclercia              
Leclercia adecarboxylata KPC - 1 - - - -
  NDM - - 1 - - -
  Other - - 1 - - -
Morganella              
Morganella morganii OXA48 - - 1 - - -
Proteus              
Proteus mirabilis NDM 5 1 - 1 - -
  OXA48 1 - - - - -
  Other 1 2 - 1 - -
Raoultella              
Raoultella ornithinolytica OXA48 1 - - 1 - -
  Other - - - 1 - -

Other carbapenemase-producing Gram-negative organisms

For all Carbapenemase-producing Gram-negative organisms, the reports are de-duplicated by first mention of organism species and resistance mechanism by person in a rolling 52-week period.

Note: the numbers presented here do not include specimens that have been referred to.

Week notification received 2025/47 2025/48 2025/49 2025/50 2025/51 2025/52 2026/00
Acinetobacter                
Acinetobacter baumannii IMP - - 1 - - - -
  NDM 1 1 - - 1 - -
  Other 1 - 1 - 1 - -
Other acinetobacter spp NDM 1 - - - - - -
Pseudomonas                
Pseudomonas aeruginosa IMP 1 1 - 1 - - -
  NDM - 1 2 - 1 - -
  VIM - 2 1 - - - -
  Other 2 3 1 3 1 1 -
Pseudomonas putida group NDM - 1 - - - - -
Other                
  KPC - - - - - 1 -
  NDM - - - - 1 - -
  OXA48 - 1 - - 1 - -