### Animal and Plant Health Inspection Service Consideration of the Status of Rinderpest in South

America

August 20112 Table of Contents Executive Summary ............................................................................................................ 3

Introduction .................................................................................................................. ....... 4 Rinderpest Virus and Epidemiology of the Disease ........................................................... 4 Global Distribution of Rinderpest ....................................................................................... 5 Rinderpest in South America .......................................................................................... 5

Conclusion .................................................................................................................... ...... 6 Appendix 1: Rinderpest in South Am erica, 1996 – 2004; Handistatus II ......................... 7 Appendix 2: Current Rinderpest Status of Africa, Asia, and Europe* .............................. 7 Appendix 3: Remaining Rinderpest Foci, 1980s - 2000 .................................................... 8

References .................................................................................................................... ....... 9

Abbreviations APHIS Animal and Plant Health Inspection Service CFR Code of Federal Regulations FAO Food and Agriculture Organization

FMD Foot-and-Mouth Disease GREP Global Rinderpest Eradication Campaign RPV Rinderpest Virus

USDA United States De partment of Agriculture3 Executive Summary

Historically, rinderpest was a prominent dis ease in U.S. laws, regulations, and trade matters because of its global distribution a nd incidence. The Tariff Act of 1930 mandated that imported animals and meat products onl y come from countries that were free of rinderpest and foot-and-m outh disease (FMD).

Currently, the Animal and Plant Health Inspec tion Service (APHIS) c ontinues to evaluate the FMD and rinderpest status of foreign regi ons, as requested by the competent authority of the region. Regions that AP HIS recognizes as free of these diseases are listed in title 9

of Code of Federal Regulations (9 CFR) part 94.1 and 9 CFR 94.11. Once listed, imports of susceptible live animals and products from susceptible species originating in or transiting these regions are no longer prohibited (or are pe rmitted with restrictions) because of FMD or rinderpest.

In-depth evaluations assessing the FMD status of South American countries are necessary because of the presence of FMD in certain regions of South America. However, rinderpest has never been established in S outh America and no South American countries have ever reported the disease except Brazil, which had an outbreak in 1921 that was limited in scope and quickly eradicated. Furthe rmore, the global distribution of rinderpest has diminished significantly in recent year s as a result of the Food and Agriculture Organization’s (FAO’s) Global Rinderpest Eradication Progr am (GREP). The last known cases of rinderpest occurred in the southern part of the “Somali pastoral ecosystem” consisting of southern Somalia, eastern Ke nya, and southern Ethi opia. In May 2011, the World Organization for Animal Health (OIE) announced its r ecognition of global rinderpest freedom.

Given that rinderpest has never established in South America, an incursion of rinderpest into that region would likely re sult in the classical, acute form of the disease, due to the availability of naïve susceptib le populations. Given the ove rt clinical signs of acute rinderpest, such an outbreak would likely be detected.

APHIS therefore proposes to recognize South America free of rinderpest. The countries

of South America would be added to the list of countries that APHI S considers free of rinderpest. Upon request, APHIS will continue to evaluate the FMD status of South American countries or regions in accordance with 9 CFR 92.2.4 Introduction

The United States Department of Agriculture’s (USDA’s) import regulati ons and trade policies for animals and animal products ar e rooted in a number of Acts, including multiple Tariff Acts of the early 1900s (e.g. the Underwood Tariff Act of 1913 and the Fordney-McCumber Tariff Act of1922) [1]. Of particular significance was the SmootHawley Tariff Act of 1930, whic h expanded previous restric tions on animals and meat by prohibiting the importation of cattle, sheep, sw ine, and meats from countries in which rinderpest or FMD existed [2]. At that time, and well into the mi d-1900’s, rinderpest was widespread throughout Asia, parts of Europe, and Africa [3, 4].

Currently, when requested to do so by the co mpetent authority of a potential or existing international trading partner, APHIS evaluate s and codifies in 9 CFR 94.1 the rinderpest and FMD status of foreign regions. APHIS us es an animal health evaluation process, outlined in 9 CFR 92.2, which includes a ssessments of the region’s veterinary infrastructure, disease status and controls, surveillance efforts, di agnostic capability, and related factors. Where appropriate, the evaluations outline constraints, hindrances, or limitations in the foreign region, and identify a ny mitigations for associated risks. If the

evaluation results are favorable APHIS proposes a rule to recognize a country or region as “free of both rinderpest and foot-and-mouth disease” or “free of rinderpest.” If recognized as free of rinder pest and FMD, imports of live susceptible species and products from these animals originating in or transiting these regions are no longer prohibited (or are permitted with restrictions) because of FMD or rinderpest. In Section 94.11 of the CFR, APHIS further designates regi ons of the world recognized as free of rinderpest and FMD but subject to certain restrictions because of their proximity to or trading practices with rinderpe st or FMD-affected regions.

Rinderpest Virus and Epidemiology of the Disease

Rinderpest virus (RPV), a Morbillivirus, exists as a single serotype [5]. The virus is molecularly grouped into three di stinct lineages (African linea ge 1, African lineage 2, and Asian lineage 3) based on evolutionary diverg ence [5, 6]. Close contact is required for viral spread. The virus is not vertically transmitted, and there are no arthropod vectors [7]. RPV has a short infectious period; it has no latency period and does not result in persistent infection [8]. RPV infection does not induce a carrier state [5], and vaccination against RPV yields a long duration of immun ity [5]. The virus is fragile and rapidly inactivated by heat and light, but does remain viable for long periods in chilled or frozen tissues [9]. RPV detectability is low in pr oducts, but so is RPV survivability. A single waste-feeding incident with rinderp est has been documented [5].

Rinderpest disease is characterized by fever, necrotic stomatitis, ga stroenteritis, profuse diarrhea, dehydration, and high mortality [9, 10]. Rinderpest typically presents as an acute disease with overt signs including fever, oculo-nasal discharges, mucosal necrosis and erosions, and ulcerations in the digest ive and upper respirator y tracts [10]. Although cattle are the primary reservoir, RPV causes severe disease in many species of wildlifeand susceptible game species [5]. The acute form of disease has been observed in clovenhoofed animals such as the buffalo, ela nd, giraffe, lesser kudu, and warthog [11].5 However, there is no evidence that wildlife serv e as a reservoir for the virus. Rather, it is believed that cattle are the maintenance hosts, and if the virus is not present in cattle, it will disappear in wildlife [7]. The diseas e is associated with high morbidity and mortality; the classical acute form of the di sease can result in 80-90% mortality in cattle, buffalo, yaks, and many wildlif e ungulate speci es [12, 13].

A mild form of rinderpest, with wide varia tions in disease frequency and intensity, has been observed. Morbidity and mortality rates vary, both ranging from 0 – 10%, and classical clinical or epidemiological feat ures may be lacking [10], which poses a challenge for disease detection. The mild form of rinderpest is most clearly demonstrated in lineage 2 viruses from East Africa [14], but has been observed with all three RPV lineages [5]. Outbreaks of the mild form of rinderpest have occurre d in Egypt (African lineage 1), Kenya (African lin eage 1), northern Iraq (Asian lineage 3), and the Somali pastoral ecosystem (African lineage 2) [5].

The mild form of rinderpest has been observed in highly endemic areas and in populations with some inherited resistance [10]. Wh en rinderpest first occurs in a naïve population, its virulence increase s, and when the virus becomes endemic, its virulence decreases [5]. Accordingly, the selection pre ssure for rinderpest vi rulence is affected by

the disease situation and immune status of potential hosts in an area, with populations of naïve cattle presenting a sele ction pressure for virulence, and populations of partially immune cattle presenting a selection pressure for attenuation [5]. It is highly unlikely that the mild form of rinderpest exists in South America, because rinderpest has never established itself in that part of the world. Further, because wild and domestic susceptible species there would be naïve, any future RPV introduction into South America would likely result in the acute, classical form of disease, which, by way of high morbidity and/or mortality, woul d be detectable.

Global Distribution of Rinderpest

Historically, rinderpest has been widely di stributed throughout Eu rope, Asia, and Africa

but has never been established in North America, Central America, the Caribbean Islands, South America, Australia, or New Zealand. Virtually the entire history of rinderpest occurrence is in Europe, Russia, the Middle and Far East , India and Pakistan, Africa, and the Arabian peninsula [5]. As evident in Appendix 3, the incidence of rinderpest has declined significantly over th e course of the last 20 years and its geographic distribution has been confined over the last decade. As reported by GREP, the only remaining known focus for rinderpest is th e southern part of the ‘Somali pastoral ecosystem’ (southern Somalia, eastern Kenya, and southern Ethiopia) [8, 15-18]. In May 2011, based on the conclusion that rinderpest has ceased to circulate in animals, the OIE announced its recognition of gl obal rinderpest freedom [19].

Rinderpest in South America

In addition to significant decline in the globa l distribution of rinderp est in recent years (Appendix 3), rinderpest has neve r established in South Amer ica. Rinderpest has never been detected in any South American country with the exception of a single incursion in

Brazil in 1921. Zebu cattle infect ed in Belgium were shipped to Brazil and introduced the6 disease, which occurred first in work oxen, and then spread to dairy herds and wild deer. By use of quarantines, movement controls of livestock, and slaughterof all sick and incontact animals, the outbreak was limited in scope and eradicated within 3 months. The last official report of a case of the di sease was on May 23, 1921, and restrictions were lifted in August of that year [4, 5, 20, 21] with no subsequent di sease occurrence.

Given that rinderpest has not occurred in South America since 1921 and the wide host range of susceptible domestic and wildlife species in South America, the most likely expression of a rinderpest incursion would be th e acute, classical form of the disease. It is therefore likely that, if introduced into S outh America, rinderpest would be detected.

Conclusion

APHIS concludes that the historical absen ce of rinderpest in South America supports recognition of South America as free of rinderp est. APHIS also concludes that a future incursion of rinderpest into South America would likely ma nifest as the acute, classical form of the disease, and w ould likely be detected. APHIS therefore proposes to recognize South America free of rinderpest. The countri es of South America will be added to the list of countries that APHIS considers free of rinderpest. APHIS will continue to

evaluate the FMD status of South American countries or regions upon request and in

accordance with 9 CFR 92.2.7 Appendix 1: Rinderpest in South America, 1996 – 2004; Handistatus II

Country/Territory 1996 1997 1998 1999 2000 2001 2002 2003 2004

Argentina 0000 0000 0000 0000 0000 0000 0000 0000 0000

Bolivia 0000 0000 0000 0000 0000 0000 0000 0000 0000

Brazil (1921) (1921) (1921) (1921) (1921) (1921) (1921) (1921) (1921)

Chile 0000 0000 0000 0000 0000 0000 0000 0000 0000

Colombia 0000 0000 0000 0000 0000 0000 0000 0000 0000

Ecuador 0000 0000 0000 0000 0000 0000 0000 0000 0000

French Guiana 0000 0000 0000

- - - - - Guyana 0000 0000 0000

Paraguay 0000 0000 0000 0000 0000 0000 0000 0000

Peru 0000 0000 0000 0000 0000 0000 0000 0000 0000

Suriname 0000

- - Uruguay 0000 0000 0000 0000 0000 0000 0000 0000 0000

Venezuela 0000 0000 0000 0000 0000 0000 0000 0000 0000

Note: Rinderpest status of South American countries as reported to the World Organization for Animal Health (OIE). 0000 = disease never reported. - = di sease not reported (date of last outbreak not known)

Appendix 2: Current Rinderpest Stat us of Africa, Asia, and Europe*

Source: http://www.fao.org/ag/againfo/pr ogrammes/en/empres/disease_rinderpest.asp *Freedom/provisional freedom defined by the procedures laid out in the OIE’s Terrestrial Animal Health Code [22]. OIE-recognition is not always reflected in Handistatus data. For example, Rwanda is recognized “free from infection” by OIE yet Handistatus II has no available data on Rwanda.8 Appendix 3: Remaining Rinderpest Foci, 1980s - 2000

Figure 1: Distribution of rinderpest in Africa , Europe, and Asia in the early 1980s [15]

Figure 2: Distribution of rinderpest in Africa , Asia, and Europe in the late 1990s [15]

Figure 3: Rinderpest zones of risk in Af rica, Asia, and Europe as of 2000 [15]

Somali pastoral ecosystem9 References

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