Research and analysis

NOIDs causative agents: week 50 (week ending 14 December 2025)

Updated 15 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 2025/45 2025/46 2025/47 2025/48 2025/49 2025/50
Arboviruses            
West Nile Virus 2 - - - - -
Bacillus            
Bacillus cereus 14 26 23 21 22 19
Bordetella            
Bordetella pertussis 2 5 1 3 6 4
Borrelia            
Borrelia burgdorferi 42 39 20 39 21 32
Borrelia other named - - 1 - - -
Borrelia sp 6 3 5 4 7 4
Brucella            
Brucella sp 2 2 3 2 1 2
Campylobacter            
Campylobacter coli 31 31 28 24 19 14
Campylobacter fetus 1 - 1 4 - -
Campylobacter gracilis 1 1 - - - -
Campylobacter jejuni 330 312 277 220 275 254
Campylobacter other named 1 1 1 1 1 2
Campylobacter rectus - - 1 1 - -
Campylobacter sp 1,003 978 877 916 824 932
Campylobacter upsaliensis - 1 1 - 1 -
Campylobacter ureolyticus (bacteroides corrodens) 1 - - 1 1 1
Chikungunya virus            
Chikungunya virus 1 2 - 1 1 2
Clostridium            
Clostridium perfringens 42 36 41 55 38 32
Coronavirus            
Coronavirus 31 24 27 32 54 77
Human coronavirus 229e - 6 - 5 3 5
Human coronavirus hku1 - - - - - 1
Human coronavirus nl63 1 1 - - - 3
Human coronavirus oc43 - 1 1 1 - 2
SARS-CoV-2 antibody indeterminate 4 - - - - -
SARS-CoV-2 antibody void 20 12 6 - - -
SARS-CoV-2 coronavirus (COVID-19) 1,400 805 638 715 790 1,348
SARS-CoV-2 coronavirus (COVID-19) indeterminate 36 42 24 28 71 50
SARS-CoV-2 IgG antibody negative 5 8 5 2 6 10
SARS-CoV-2 IgG antibody positive 48 60 48 49 50 77
SARS-CoV-2 total antibody negative 8 12 4 8 8 -
SARS-CoV-2 total antibody positive 36 45 15 37 19 19
Corynebacterium            
Corynebacterium diphtheriae 7 8 2 2 4 6
Corynebacterium ulcerans 1 - - - - 1
Coxiella            
Coxiella burnetii - - - - 1 1
Cryptosporidium            
Cryptosporidium cuniculus - 2 2 1 - -
Cryptosporidium felis 1 - - - - -
Cryptosporidium hominis 17 13 8 2 6 -
Cryptosporidium meleagridis - - 2 - - -
Cryptosporidium parvum 20 35 29 19 17 7
Cryptosporidium sp 54 34 42 58 67 75
Cryptosporidium ubiquitum - - - 1 - -
Entamoeba            
Entamoeba histolytica 4 1 4 2 4 4
Escherichia            
Escherichia coli O 157 10 14 11 12 11 3
Flaviviruses            
Dengue virus 12 9 4 6 3 3
Giardia            
Giardia intestinalis - 1 - - - -
Giardia sp 138 137 143 123 145 124
Haemophilus            
Haemophilus influenzae 76 66 46 74 68 61
Hepatitis viruses            
Hepatitis A 18 19 17 32 12 14
Hepatitis B 232 290 241 237 268 238
Hepatitis C 254 235 229 210 263 216
Hepatitis D 10 2 3 3 6 5
Hepatitis E 26 53 21 39 25 32
Influenza virus            
Influenza A 3,910 3,503 3,851 6,936 9,142 9,443
Influenza B 51 43 56 72 45 69
Influenza indeterminate 5 11 15 9 12 18
Influenza ungrouped 95 61 88 148 217 217
Legionella            
Legionella longbeachae - - - - 1 -
Legionella pneumophila 11 8 5 4 2 7
Legionella sp 7 3 7 4 4 7
Leptospira            
Leptospira interrogans - 1 - - - -
Listeria            
Listeria monocytogenes 3 2 10 4 3 7
Mycobacterium            
Mycobacterium tuberculosis 114 87 101 87 91 77
Neisseria            
Neisseria meningitidis 28 35 35 27 41 40
Orthopoxvirus            
Mpox virus positive 7 15 19 12 12 6
Paramyxoviruses            
Measles virus 8 14 7 25 11 11
Mumps virus 5 7 4 2 5 8
Plasmodium            
Plasmodium falciparum - - 3 14 - -
Plasmodium malariae - - - 2 - -
Plasmodium ovale - - - 3 - -
Plasmodium vivax - - - 2 - -
Polyomavirus            
Polyomavirus BK 60 60 49 71 73 76
Polyomavirus JC 13 15 14 7 2 18
Polyomavirus untyped 6 17 16 12 10 13
Rickettsia            
Rickettsia prowazekii - - - 1 - -
Rickettsia rickettsii - - - 1 - -
Rickettsia spotted fever - - - - 1 -
Rickettsia tsutsugamushi - - - - - 1
Rubella virus            
Rubella virus 6 2 1 1 1 3
Salmonella            
Other salmonellas 61 54 65 50 37 21
Salmonella agona - - - - 5 -
Salmonella bareilly 5 - 7 6 - -
Salmonella chester 8 5 5 - - -
Salmonella enterica - 5 - 5 - -
Salmonella enteritidis 71 73 71 60 25 10
Salmonella infantis - 7 6 - - -
Salmonella java - 7 - - - -
Salmonella kentucky - - - 6 - -
Salmonella newport 11 8 13 6 - -
Salmonella saint-paul - 6 - 8 - -
Salmonella sp 24 16 35 44 88 124
Salmonella stanley - - - 5 - -
Salmonella typhi and paratyphi 9 10 13 14 10 8
Salmonella typhimurium 31 44 23 22 16 13
Shigella            
Shigella boydii 4 2 2 1 1 1
Shigella dysenteriae - - 1 - - 1
Shigella flexneri 20 20 20 18 9 13
Shigella sonnei 49 35 34 45 32 23
Shigella sp 99 80 65 61 60 60
Streptococcus            
Streptococcus group A 42 71 57 41 56 54
Streptococcus pneumoniae 127 123 99 100 146 132
Vibrio            
Vibrio cholerae 1 - - 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 2025/45 2025/46 2025/47 2025/48 2025/49 2025/50
Citrobacter              
Citrobacter spp IMP 1 1 - - - -
  KPC - 1 1 1 - -
  NDM 2 - 5 1 - 1
  OXA48 3 1 3 - 4 -
  Other - - 1 - - -
Enterobacter              
Enterobacter cloacae complex IMP - - 5 - 1 -
  KPC 3 4 4 4 4 1
  NDM 3 4 10 6 6 1
  OXA48 1 2 2 5 7 -
  Other 1 - 3 1 1 -
Other enterobacter spp NDM 1 - - - - -
  OXA48 - - 1 - - -
Escherichia              
Escherichia coli IMP 1 1 - - 1 -
  KPC 8 - 4 3 4 1
  NDM 12 32 15 12 20 2
  OXA48 21 32 32 26 26 10
  VIM - - 1 - 1 -
  Other 1 3 3 3 3 1
Klebsiella              
Klebsiella aerogenes IMP 1 - - - - -
  OXA48 1 - - - 2 -
Klebsiella oxytoca KPC - 1 1 1 1 -
  NDM 2 - - 1 - -
  OXA48 - - 1 - 2 -
  VIM - - - 1 - -
  Other - - - 1 1 -
Klebsiella pneumoniae IMP - - 1 - 2 1
  KPC 8 8 12 15 8 -
  NDM 9 13 10 10 7 -
  OXA48 12 15 14 13 10 4
  VIM - - - - 1 -
  Other 3 3 1 1 3 -
Klebsiella variicola KPC - - - 1 - -
  OXA48 1 - - - - -
Other klebsiella spp KPC 1 - - - - -
Leclercia              
Leclercia adecarboxylata KPC - - - 1 - -
  NDM - - - - 1 -
  Other - - - - 1 -
Proteus              
Proteus mirabilis NDM 2 1 5 1 - -
  OXA48 - - 1 - - -
  Other 1 1 1 1 - -
Providencia              
Providencia rettgeri (proteus rettgeri) NDM - 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 2025/45 2025/46 2025/47 2025/48 2025/49 2025/50
Acinetobacter              
Acinetobacter baumannii IMP - - - - 1 -
  NDM - - 1 1 - -
  Other - 1 1 - 1 -
Other acinetobacter spp NDM - - 1 - - -
Pseudomonas              
Pseudomonas aeruginosa IMP 1 - 1 1 - 1
  NDM 2 - - 1 2 -
  VIM 2 1 - 2 - -
  Other 2 1 2 3 2 2
Pseudomonas putida group NDM - - - 1 - -
  VIM 1 1 - - - -
Other              
  NDM 1 - - - - -
  OXA48 - - - 1 - -