Animal Trypanosomiasis

LEVELS: NOT ASSIGNED; NOT ASSIGNED; Extraordinary biosecurity required; Reference or research laboratory required; NOT ASSIGNED; NOT ASSIGNED; Some; NOT ASSIGNED


Register id	`trypanosoma_spp`
Type	parasite
Scientific name	Trypanosoma
NCBI taxid	5690
Evidence	3 document(s)
Assigned	2026-09-04, against criteria version `093366e352a2`

Overview

This is a genus-level entry covering animal trypanosomiasis as a single assessment unit, and it exists as a deliberate test of how little the register can know about an agent. There is no Diseases of Swine chapter; the evidence is three factsheets covering three quite different diseases — African animal trypanosomiasis or nagana, transmitted by tsetse flies; American trypanosomiasis, the Chagas agent T. cruzi, transmitted by triatomine bugs; and surra, T. evansi, spread mechanically by biting flies. Pigs appear in all three but rarely as the focus. Several African species use pigs among their reservoir hosts, and T. suis, T. godfreyi and T. simiae specifically affect pigs and wild African suids such as warthogs. None of these agents has ever caused an event in US pigs, and no market or trade consequence involving pigs is described anywhere. Trypanocidal drugs exist but few are effective, availability outside endemic areas is poor, and protocols for less usual hosts have to be chosen carefully because efficacy and toxicity vary by species. There is no vaccine; control is vector reduction and treating reservoir animals. Because the material supports almost no claim about the disease in pigs, five of this entry's eight criteria were deliberately left unscored.

C1 Zoonotic potential

Likelihood of transmission from pigs to humans

NOT ASSESSED — no evidence in folder. No level was assigned on this criterion. This is a statement about what the evidence folder holds, not a finding about the agent.

Corrected by Eric from L1 Highly unlikely. Reason: RULED NOT ASSESSABLE AND ROUTED TO KISS ANALYSIS, 2026-09-03. Against C1, C2, C5, C6 and C8 he wrote "KISS", adding on C6 "WE DON'T REALLY KNOW BECAUSE WE DON'T KNOW ABOUT PRODUCTION IMPACT" -- which states the dependency the pass had built into those cells and resolves it downward. HE PREDICTED THIS ENTRY WOULD COME OUT THIS WAY on 2026-08-28, when it was registered: "I suspect already, ther will be insufficient evidence to make a clear analysis." THE FOLDER IS THREE CFSPH FACTSHEETS WRITTEN ABOUT OTHER SPECIES -- African animal trypanosomiasis, Chagas disease and surra -- two of them marked thin on the pig question, and the governing sentence is "there is RELATIVELY LITTLE INFORMATION ABOUT PIGS, which often seem to carry trypanosomes subclinically". NOTE WHICH THREE CELLS HE KEPT: C3 at level 4 ("arthropod vector means air filters likely required to keep it out if it happened to reach the us and find a vector"), C4 at level 3 ("would almost certainly take a reference lab to confirm"), and C7 at level 2, which never reached the gaps sheet because it was supported. The KISS route is being applied CELL BY CELL: what is known about how to exclude it and how to detect it survives; what is claimed about the disease does not.

Basis. NO DISEASES OF SWINE CHAPTER, AND THE ENTRY IS THE WHOLE GENUS -- "Animal Trypanosomiasis", anchored at Trypanosoma. The folder is three CFSPH factsheets covering three different diseases: AFRICAN animal trypanosomiasis (nagana, tsetse-borne), AMERICAN trypanosomiasis (T. cruzi, Chagas, triatomine-borne) and SURRA (T. evansi, mechanically fly-borne). Two of the three are marked thin on the pig question. You predicted this: "I suspect already, ther will be insufficient evidence to make a clear analysis." WHAT THE FOLDER SAYS ABOUT PIGS SPECIFICALLY, which is the whole of it. cfsph_2024_african: "While agents such as T. congolense, T. vivax and T. b. brucei can be found in a number of hosts, WITH RESERVOIRS IN CATTLE, SMALL RUMINANTS, PIGS AND SOME WILDLIFE, T. SUIS ONLY SEEMS TO INFECT DOMESTIC PIGS AND WILD AFRICAN SUIDS such as warthogs. T. godfreyi and T. simiae also affect pigs." And: "THERE IS RELATIVELY LITTLE INFORMATION ABOUT PIGS, WHICH OFTEN SEEM TO CARRY TRYPANOSOMES SUBCLINICALLY; however, T. SIMIAE WAS REPORTED TO CAUSE A HYPERACUTE ILLNESS IN THIS SPECIES, WITH DEATH OFTEN OCCURRING WITHIN 48 HOURS of the initial signs, while EXPERIMENTAL T. SUIS INFECTION WAS CHARACTERIZED BY SEVERE ACUTE DISEASE IN PIGLETS AND CHRONIC INFECTIONS IN ADULTS... ADULT PIGS OFTEN SEEM TO BE RELATIVELY RESISTANT TO CLINICAL SIGNS, BUT YOUNG ANIMALS CAN BE MORE SUSCEPTIBLE." cfsph_2024_american places pigs inside a 150-species host list for T. cruzi with a Mexican fattening-pig serosurvey; cfsph_2024_surra places suids in a broad host list and names feral pig as a possible maintenance host in sylvatic Brazil. ON THE HUMAN SIDE, the folder covers diseases that are unambiguously serious in people -- sleeping sickness and Chagas disease -- but NOWHERE ATTRIBUTES A HUMAN CASE TO A PIG. The reservoirs named for the human-infective agents are other species, and every route described is through an insect vector rather than from an animal to a person.

How this level was decided

INFERRED, AND FLAGGED, because this is a genus entry that mixes agents of great human importance with agents that only infect pigs, and the criterion asks about one narrow thing. LEVEL 1 -- no evidence that PIGS transmit these agents to humans. C1 was rescoped on your chikungunya ruling to ask about the pig-to-human route specifically, and none of the three factsheets describes one: human African trypanosomiasis and Chagas disease are acquired from tsetse flies and triatomine bugs, and the pig-adapted agents in this genus -- T. suis, T. simiae, T. godfreyi -- are not human pathogens. NOTE THE TRAP THIS CELL AVOIDS AND WHY IT MATTERS FOR THE REPORT: sleeping sickness and Chagas are frightening diseases, and a reader who sees this genus scored at level 1 will assume an error unless the label is printed in full. It says pigs are not the source, not that trypanosomes are harmless.

C2 Zoonotic impact

Severity of human illness caused by the agent

NOT ASSESSED — no evidence in folder. No level was assigned on this criterion. This is a statement about what the evidence folder holds, not a finding about the agent.

Corrected by Eric from L1 No human illness. Reason: RULED NOT ASSESSABLE AND ROUTED TO KISS ANALYSIS, 2026-09-03. Against C1, C2, C5, C6 and C8 he wrote "KISS", adding on C6 "WE DON'T REALLY KNOW BECAUSE WE DON'T KNOW ABOUT PRODUCTION IMPACT" -- which states the dependency the pass had built into those cells and resolves it downward. HE PREDICTED THIS ENTRY WOULD COME OUT THIS WAY on 2026-08-28, when it was registered: "I suspect already, ther will be insufficient evidence to make a clear analysis." THE FOLDER IS THREE CFSPH FACTSHEETS WRITTEN ABOUT OTHER SPECIES -- African animal trypanosomiasis, Chagas disease and surra -- two of them marked thin on the pig question, and the governing sentence is "there is RELATIVELY LITTLE INFORMATION ABOUT PIGS, which often seem to carry trypanosomes subclinically". NOTE WHICH THREE CELLS HE KEPT: C3 at level 4 ("arthropod vector means air filters likely required to keep it out if it happened to reach the us and find a vector"), C4 at level 3 ("would almost certainly take a reference lab to confirm"), and C7 at level 2, which never reached the gaps sheet because it was supported. The KISS route is being applied CELL BY CELL: what is known about how to exclude it and how to detect it survives; what is claimed about the disease does not.

How this level was decided

INFERRED. Level 1, following C1 -- C1 level 1 implies C2 level 1 and validate_criteria.py enforces it per entry. AS WITH EBOLA VIRUS EARLIER TONIGHT, THE PRINTED LABEL MUST BE THE FULL ONE wherever this entry is excerpted: "No human disease from pigs". Human African trypanosomiasis and Chagas disease kill people; they do not get them from pigs, and that is the only claim this cell makes.

C3 Herd introduction risk

Effort required to keep the agent out of the herd

Extraordinary biosecurity required: Exclusion needs measures beyond the routine, such as air filtration, thermally treated feed and bedding, or repeated costly testing to find carriers, and may still fail

CONFIRMED by Eric. The assignment reached this level from the evidence, and he has reviewed and ratified it.

Confirmed by Eric. CONFIRMED. "C3l4, arthropod vector means air filters likely required to keep it out if it happened to reach the us and find a vector"

How this level was decided

INFERRED. Level 4 -- extraordinary biosecurity required, and it may still fail. THE ROUTE IS AN INSECT, and your 2026-09-03 test is explicit that housing closes the route when it is the ground the pig stands on, and DOES NOTHING WHEN THE ROUTE IS SOMETHING THAT FLIES. Chikungunya virus sits at level 4 on exactly this reasoning. What the folder offers as protection is insect screens and netting, repellents and traps -- which is the level 4 list rather than the level 3 one -- and it says even that gives only "SOME DEGREE OF PROTECTION". NOTE THE ASYMMETRY IN THE ENTRY, since it is a genus: the African agents cannot establish here at all without tsetse, so for them the practical answer is that the vector is the barrier; T. cruzi already has a competent vector in the southern US. The level is scored on the agents that could actually arrive.

C4 Detection difficulty

Difficulty of recognizing and confirming infection

Reference or research laboratory required: A validated assay exists, but only at a national reference or research laboratory rather than at local or regional level

CONFIRMED by Eric. The assignment reached this level from the evidence, and he has reviewed and ratified it.

Confirmed by Eric. CONFIRMED. "C4l3, would almost certainly take a reference lab to confirm the infection, not avaialble as part of routine tests at local or regional US labs"

How this level was decided

INFERRED. Level 3 -- a validated assay exists but at national reference or research laboratory level rather than locally. Microscopy, serology and culture are all established techniques for this genus, so this is not level 4; but culture takes weeks to months and requires expertise, animal inoculation is the fallback, the disease is immediately reportable in the US, and a WOAH reference laboratory exists for it. That is the same structural answer as classical swine fever and African swine fever. NOT LEVEL 2: no US regional laboratory is looking for trypanosomes in a pig, and there is no clinical presentation that would prompt them to.

C5 Production cost

Financial impact on the infected farm's cost of production

NOT ASSESSED — no evidence in folder. No level was assigned on this criterion. This is a statement about what the evidence folder holds, not a finding about the agent.

Corrected by Eric from L3 Moderate. Reason: RULED NOT ASSESSABLE AND ROUTED TO KISS ANALYSIS, 2026-09-03. Against C1, C2, C5, C6 and C8 he wrote "KISS", adding on C6 "WE DON'T REALLY KNOW BECAUSE WE DON'T KNOW ABOUT PRODUCTION IMPACT" -- which states the dependency the pass had built into those cells and resolves it downward. HE PREDICTED THIS ENTRY WOULD COME OUT THIS WAY on 2026-08-28, when it was registered: "I suspect already, ther will be insufficient evidence to make a clear analysis." THE FOLDER IS THREE CFSPH FACTSHEETS WRITTEN ABOUT OTHER SPECIES -- African animal trypanosomiasis, Chagas disease and surra -- two of them marked thin on the pig question, and the governing sentence is "there is RELATIVELY LITTLE INFORMATION ABOUT PIGS, which often seem to carry trypanosomes subclinically". NOTE WHICH THREE CELLS HE KEPT: C3 at level 4 ("arthropod vector means air filters likely required to keep it out if it happened to reach the us and find a vector"), C4 at level 3 ("would almost certainly take a reference lab to confirm"), and C7 at level 2, which never reached the gaps sheet because it was supported. The KISS route is being applied CELL BY CELL: what is known about how to exclude it and how to detect it survives; what is claimed about the disease does not.

Basis. NO DISEASES OF SWINE CHAPTER, AND THE ENTRY IS THE WHOLE GENUS -- "Animal Trypanosomiasis", anchored at Trypanosoma. The folder is three CFSPH factsheets covering three different diseases: AFRICAN animal trypanosomiasis (nagana, tsetse-borne), AMERICAN trypanosomiasis (T. cruzi, Chagas, triatomine-borne) and SURRA (T. evansi, mechanically fly-borne). Two of the three are marked thin on the pig question. You predicted this: "I suspect already, ther will be insufficient evidence to make a clear analysis." WHAT THE FOLDER SAYS ABOUT PIGS SPECIFICALLY, which is the whole of it. cfsph_2024_african: "While agents such as T. congolense, T. vivax and T. b. brucei can be found in a number of hosts, WITH RESERVOIRS IN CATTLE, SMALL RUMINANTS, PIGS AND SOME WILDLIFE, T. SUIS ONLY SEEMS TO INFECT DOMESTIC PIGS AND WILD AFRICAN SUIDS such as warthogs. T. godfreyi and T. simiae also affect pigs." And: "THERE IS RELATIVELY LITTLE INFORMATION ABOUT PIGS, WHICH OFTEN SEEM TO CARRY TRYPANOSOMES SUBCLINICALLY; however, T. SIMIAE WAS REPORTED TO CAUSE A HYPERACUTE ILLNESS IN THIS SPECIES, WITH DEATH OFTEN OCCURRING WITHIN 48 HOURS of the initial signs, while EXPERIMENTAL T. SUIS INFECTION WAS CHARACTERIZED BY SEVERE ACUTE DISEASE IN PIGLETS AND CHRONIC INFECTIONS IN ADULTS... ADULT PIGS OFTEN SEEM TO BE RELATIVELY RESISTANT TO CLINICAL SIGNS, BUT YOUNG ANIMALS CAN BE MORE SUSCEPTIBLE." cfsph_2024_american places pigs inside a 150-species host list for T. cruzi with a Mexican fattening-pig serosurvey; cfsph_2024_surra places suids in a broad host list and names feral pig as a possible maintenance host in sylvatic Brazil. On severity across hosts generally, cfsph_2024_african: "In fully susceptible, untreated ruminants, trypanosomes SOMETIMES RESULT IN 50-100% MORTALITY WITHIN MONTHS, especially when poor nutrition or other factors contribute to debilitation. However, African animal trypanosomiasis is NOW MOSTLY A DISEASE OF HIGH MORBIDITY BUT LOW MORTALITY in Africa, DUE TO THE AVAILABILITY OF ANTITRYPANOSOMAL DRUGS." "Some animals remain subclinically infected... while others develop chronic illnesses of varying severity or acute cases that may be rapidly fatal."

How this level was decided

INFERRED, AND FLAGGED -- this is the cell you predicted would be thin and it is the hardest one in the entry. LEVEL 3 IS SCORED: losses that measurably increase cost of production but remain manageable. The pig-specific evidence pulls in two directions within a single sentence -- most pigs carry these organisms subclinically and adults are relatively resistant, but T. simiae kills in 48 hours and T. suis produces severe acute disease in piglets. THE GENERAL CASE, WHICH IS WHAT A LEVEL CLAIMS UNDER YOUR MENANGLE RULE, is high morbidity and low mortality in a treatable disease. THE ARGUMENT FOR LEVEL 4 is the hyperacute T. simiae picture; THE ARGUMENT FOR LEVEL 2 OR A NULL is the sentence that governs the whole entry -- "there is RELATIVELY LITTLE INFORMATION ABOUT PIGS". I have not nulled it because the folder does give a clinical picture, unlike coxiella where the authors declined to give one. If you think three factsheets written about other species cannot carry a claim about pigs, this is a KISS cell and C7 and C8 would go with it.

C6 Market impact

Duration of material disruption to pork and pig markets

CONFIRMED NOT ASSESSABLE. No level was assigned on this criterion, and Eric has reviewed that and ruled it correct — the folder holds nothing bearing on it. This is a statement about what the evidence supports, not a finding about the agent.

Confirmed by Eric. RULED NOT ASSESSABLE AND ROUTED TO KISS ANALYSIS, 2026-09-03. Against C1, C2, C5, C6 and C8 he wrote "KISS", adding on C6 "WE DON'T REALLY KNOW BECAUSE WE DON'T KNOW ABOUT PRODUCTION IMPACT" -- which states the dependency the pass had built into those cells and resolves it downward. HE PREDICTED THIS ENTRY WOULD COME OUT THIS WAY on 2026-08-28, when it was registered: "I suspect already, ther will be insufficient evidence to make a clear analysis." THE FOLDER IS THREE CFSPH FACTSHEETS WRITTEN ABOUT OTHER SPECIES -- African animal trypanosomiasis, Chagas disease and surra -- two of them marked thin on the pig question, and the governing sentence is "there is RELATIVELY LITTLE INFORMATION ABOUT PIGS, which often seem to carry trypanosomes subclinically". NOTE WHICH THREE CELLS HE KEPT: C3 at level 4 ("arthropod vector means air filters likely required to keep it out if it happened to reach the us and find a vector"), C4 at level 3 ("would almost certainly take a reference lab to confirm"), and C7 at level 2, which never reached the gaps sheet because it was supported. The KISS route is being applied CELL BY CELL: what is known about how to exclude it and how to detect it survives; what is claimed about the disease does not.

How this level was decided

NOT ASSESSED, under the standing note SCORING/market_impact and the ruling you made on hendra_virus: "I don't think we have enough info to assess. THIS IS A CASE WHERE WE HAVE ENOUGH EVIDENCE FOR SOME CRITERIA, BUT NOT FOR OTHERS." The note reserves a null for where NOTHING HAS EVER BEEN OBSERVED, and that is this cell: the African agents have never been in the Americas, surra has never been in US pigs, and T. cruzi has never produced a pig disease event anywhere. THERE IS NO FOREIGN PRECEDENT EITHER -- nagana is endemic across a third of Africa, but nobody has watched a pork market react to it, because the affected countries do not have the pig industry or the reporting to generate one. AN IMMEDIATELY REPORTABLE EXOTIC PARASITE IN US PIGS WOULD BE CONSPICUOUS, which is exactly the circumstance in which the note says to leave the cell unassessed rather than assert a duration in months.

C7 Treatment potential

Potential for treatment to improve outcomes

Some: Treatment exists but is inconsistent, requires extralabel use, or works only in some circumstances

How this level was decided

Level 2, and the chapter states the label almost clause by clause. A treatment exists and it works well enough to have changed the epidemiology of the disease across a continent, so this is not level 3. It works only in some circumstances, which the factsheet gives five ways: few effective drugs, few or none available outside endemic areas, efficacy and toxicity differing by host species with pigs among the less studied, significant drug resistance, and cure that may be clinical rather than parasitological with relapse possible. NOTE THE US POSITION, WHICH SHARPENS IT: "few or no agents may be readily available outside endemic areas" means an American veterinarian facing this would be sourcing a drug that is not on the shelf.

C8 Vaccine availability

Availability of effective vaccines or bacterins

NOT ASSESSED — no evidence in folder. No level was assigned on this criterion. This is a statement about what the evidence folder holds, not a finding about the agent.

Corrected by Eric from L1 Available, or not needed. Reason: RULED NOT ASSESSABLE AND ROUTED TO KISS ANALYSIS, 2026-09-03. Against C1, C2, C5, C6 and C8 he wrote "KISS", adding on C6 "WE DON'T REALLY KNOW BECAUSE WE DON'T KNOW ABOUT PRODUCTION IMPACT" -- which states the dependency the pass had built into those cells and resolves it downward. HE PREDICTED THIS ENTRY WOULD COME OUT THIS WAY on 2026-08-28, when it was registered: "I suspect already, ther will be insufficient evidence to make a clear analysis." THE FOLDER IS THREE CFSPH FACTSHEETS WRITTEN ABOUT OTHER SPECIES -- African animal trypanosomiasis, Chagas disease and surra -- two of them marked thin on the pig question, and the governing sentence is "there is RELATIVELY LITTLE INFORMATION ABOUT PIGS, which often seem to carry trypanosomes subclinically". NOTE WHICH THREE CELLS HE KEPT: C3 at level 4 ("arthropod vector means air filters likely required to keep it out if it happened to reach the us and find a vector"), C4 at level 3 ("would almost certainly take a reference lab to confirm"), and C7 at level 2, which never reached the gaps sheet because it was supported. The KISS route is being applied CELL BY CELL: what is known about how to exclude it and how to detect it survives; what is claimed about the disease does not.

How this level was decided

INFERRED. Level 1 on the "not needed" clause, by the FOURTH route in the standing note SCORING/vaccine_availability -- the response to an incursion would be eradication rather than vaccination. Your swine vesicular disease ruling is the precedent and it transfers without adjustment: "in the current environment, L1 is correct. If the disease became established perhaps vaccine would be a useful management tool but today, THE OBJECTIVE WOULD BE RAPID [eradication]." The factsheet says exactly that -- stamping out with vector control, if caught promptly. NOTE WHAT THIS CELL IS NOT SAYING: it is not claiming a trypanosome vaccine would be easy or that the disease is trivial where it is endemic. It is saying that for US swine, an agent not present here whose control would be quarantine and euthanasia does not present a vaccine gap worth funding. LEVEL 3 WOULD READ AS A FUNDING RECOMMENDATION FOR A PIG VACCINE AGAINST NAGANA, which is not what the evidence supports.

Levels and evidence are generated from data/assignments/trypanosoma_spp.yml; the overview is authored in data/overviews/trypanosoma_spp.md. Do not hand-edit this page — corrections go in data/assignments/CORRECTIONS.yml.

Quoted material marked Basis is from Zimmerman JJ, Karriker LA, Ramirez A, Schwartz KJ, Stevenson GW, Zhang J, eds. Diseases of Swine, 12th edition. Hoboken: Wiley Blackwell, 2025 — except where another source is named in the quotation itself.

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