This list includes 23 Viruses that start with I, from “Ibaraki virus” to “Israeli acute paralysis virus”. These viruses include animal, plant, and human pathogens with varied structures and genomes. They matter for public health, laboratory research, surveillance, and vaccine or diagnostic development.
Viruses that start with I are a diverse set of viral species whose names begin with the letter I. Notably, the Ibaraki virus is a well-known cattle pathogen first identified in Japan during the 1950s.
Below you’ll find the table with Name, Classification, Affects humans?, Symptoms, and Transmission method.
Name: The virus common name or accepted species name you use to locate and cross-check entries quickly.
Classification: The ICTV family/genus/species so you understand relationships and compare similar viruses at a glance for context.
Affects humans?: Yes/No with brief qualifier so you know zoonotic risk or clinical relevance to people quickly.
Symptoms: Typical clinical features in 5–10 words so you can recognize common presentations without excessive detail or differential clues.
Transmission method: How the virus spreads, stated succinctly so you can assess exposure routes and prevention needs.
Viruses that start with I
| Name | Classification | Affects humans? | Transmission | Description |
|---|---|---|---|---|
| Influenza A virus | Orthomyxoviridae, Alphainfluenzavirus | Yes — seasonal and pandemic | respiratory droplets, contact | Symptoms: fever, cough, muscle aches, sore throat; hosts: humans, birds, pigs; notable: causes seasonal flu and historic pandemics. |
| Influenza B virus | Orthomyxoviridae, Betainfluenzavirus | Yes — seasonal | respiratory droplets, contact | Symptoms: fever, cough, sore throat, fatigue; hosts: humans (primarily); notable: causes seasonal influenza, less antigenic diversity than A. |
| Influenza C virus | Orthomyxoviridae, Gammainfluenzavirus | Yes — usually mild | respiratory droplets, contact | Symptoms: mild respiratory illness, cough, low-grade fever; hosts: humans, pigs; notable: typically causes sporadic, mild infections. |
| Influenza D virus | Orthomyxoviridae, Deltainfluenzavirus | No — primarily cattle (possible spillover) | respiratory (cattle) | Symptoms: cattle respiratory signs; hosts: cattle and other ruminants; notable: not established as a human pathogen. |
| Ilheus virus | Flaviviridae, Flavivirus | Yes — zoonotic, rare | mosquito-borne | Symptoms: fever, headache, sometimes encephalitis; hosts: birds, humans; notable: South American flavivirus with occasional human encephalitis. |
| Inkoo virus | Peribunyaviridae, Orthobunyavirus | Yes — zoonotic | mosquito-borne | Symptoms: fever, headache, rarely encephalitis; hosts: birds, small mammals, humans; notable: circulates in northern Europe, usually mild. |
| Isfahan virus | Phenuiviridae, Phlebovirus | Yes — zoonotic | sandfly-borne | Symptoms: fever, headache, myalgia; hosts: humans, sandflies; notable: one of several sandfly fever viruses in the Middle East. |
| Ibaraki virus | Reoviridae, Orbivirus | No — livestock (cattle) | midge-borne (Culicoides) | Symptoms: fever, swallowing difficulty, salivation in cattle; hosts: cattle; notable: causes Ibaraki disease in Japan, not a human pathogen. |
| Israeli acute paralysis virus | Dicistroviridae, Aparavirus | No — honeybees (pollinators) | oral, mite-associated, contact | Symptoms: paralysis, trembling, rapid death in bees; hosts: honeybees; notable: linked to colony losses and varroa mite interactions. |
| Infectious bursal disease virus | Birnaviridae, Avibirnavirus | No — poultry | fecal–oral, contact | Symptoms: immunosuppression, diarrhea, mortality in chicks; hosts: chickens; notable: major poultry pathogen controlled by vaccination. |
| Infectious bronchitis virus | Coronaviridae, Gammacoronavirus | No — poultry | respiratory droplets, contact | Symptoms: coughing, sneezing, drop in egg production; hosts: chickens; notable: economically important avian coronavirus. |
| Infectious laryngotracheitis virus | Herpesviridae, Iltovirus | No — poultry | respiratory droplets, contact | Symptoms: severe respiratory distress and coughing in chickens; hosts: chickens; notable: controlled by biosecurity and vaccination. |
| Infectious pancreatic necrosis virus | Birnaviridae, Aquabirnavirus | No — fish | waterborne, contact | Symptoms: acute mortality, darkened viscera in fry; hosts: salmonid fish; notable: important aquaculture pathogen worldwide. |
| Infectious hematopoietic necrosis virus | Rhabdoviridae, Novirhabdovirus | No — fish | waterborne, contact | Symptoms: hemorrhage, lethargy, high juvenile mortality; hosts: salmon and trout; notable: major salmonid aquaculture virus. |
| Infectious hypodermal and hematopoietic necrosis virus | Parvoviridae (Densovirinae), Brevidensovirus | No — crustaceans (shrimp) | horizontal, vertical, environmental | Symptoms: high mortality, stunted growth in shrimp; hosts: penaeid shrimp; notable: severe shrimp aquaculture pathogen. |
| Infectious salmon anemia virus | Orthomyxoviridae, Isavirus | No — fish | waterborne, contact | Symptoms: anemia, lethargy, high mortality in salmon; hosts: Atlantic salmon; notable: causes major aquaculture outbreaks. |
| Infectious spleen and kidney necrosis virus | Iridoviridae, Megalocytivirus | No — fish | waterborne, contact | Symptoms: systemic hemorrhage, spleen/kidney necrosis in fish; hosts: many freshwater and marine fish; notable: important aquaculture disease. |
| Ikoma lyssavirus | Rhabdoviridae, Lyssavirus | Yes — potential zoonotic (no confirmed human cases) | bites/saliva | Symptoms: rabies-like encephalitis if infected; hosts: bats and mammals; notable: discovered in African carnivore, rabies-related lyssavirus. |
| Irkut virus | Rhabdoviridae, Lyssavirus | Yes — zoonotic, rare | bat bites/saliva | Symptoms: rabies-like encephalitis; hosts: bats (Asia), occasional human cases; notable: linked to fatal human infections after bat exposure. |
| Invertebrate iridescent virus 6 | Iridoviridae, Iridovirus | No — invertebrates (insects) | environmental, contact | Symptoms: iridescent coloration, reduced movement, mortality in insects; hosts: diverse invertebrates; notable: model virus for insect pathology. |
| Ictalurid herpesvirus 1 | Herpesviridae, Ictalurivirus | No — fish (catfish) | waterborne, contact | Symptoms: oral lesions, systemic disease in catfish; hosts: channel catfish; notable: important North American aquaculture pathogen. |
| Imjin virus | Hantaviridae, Orthohantavirus | No/Unknown — shrew-borne, potential zoonotic | aerosolized excreta, contact (potential) | Symptoms: hantavirus-like disease possible if zoonotic; hosts: shrews; notable: discovered in Korea; human risk unclear. |
| Iquitos virus | Peribunyaviridae, Orthobunyavirus | Yes — zoonotic/arboviral | mosquito-borne | Symptoms: febrile illness, sometimes neurological signs; hosts: humans, mosquitoes; notable: isolated in Peruvian Amazon, causes human febrile disease. |
Descriptions
Influenza A virus
Influenza B virus
Influenza C virus
Influenza D virus
Ilheus virus
Inkoo virus
Isfahan virus
Ibaraki virus
Israeli acute paralysis virus
Infectious bursal disease virus
Infectious bronchitis virus
Infectious laryngotracheitis virus
Infectious pancreatic necrosis virus
Infectious hematopoietic necrosis virus
Infectious hypodermal and hematopoietic necrosis virus
Infectious salmon anemia virus
Infectious spleen and kidney necrosis virus
Ikoma lyssavirus
Irkut virus
Invertebrate iridescent virus 6
Ictalurid herpesvirus 1
Imjin virus
Iquitos virus