Review

The Role of Small Ruminants in the Epidemiology andTransmission of Foot-and-Mouth Disease

P.V. BARNETT and S.J. COX

Institute for Animal Health, Pirbright Laboratory, Ash Road, Pirbright, Working, Surrey, GU24 0NF, UK

SUMMARY

Despite representing the largest part of the world’s foot-and-mouth disease (FMD)-susceptible domestic live-stock, sheep and goats have generally been neglected with regard to their epidemiological role. This is partlydue to the often inapparent nature of the disease in these hosts. Nevertheless, their ability to become carri-ers represents a reservoir for further infection and spread of disease, and so trade of live sheep and goatspresent a major risk of entry of FMD to disease-free countries. Research and epidemiological studies con-tinue to be necessary in order both to prevent the entry of the virus and to assist in control should the dis-ease reoccur. This review concentrates primarily on more recent studies relating to sheep and goats and, inparticular, considers the importance of these hosts in the overall epidemiology of FMD.

KEYWORDS: Foot-and-mouth disease; sheep; goats; epidemiology; transmission.

The Veterinary Journal 1999, 158, 6–13Article No. tvjl.1998.0338, available online at http://www.idealibrary.com on

INTRODUCTION

Foot-and-mouth disease virus (FMDV) is the causalagent of a highly contagious illness of more than 33domesticated or wild species of animals. In com-parison to other agriculturally important species,studies on sheep and goats have been very limited.Only in the last 30 years have small ruminantsgained any prominence experimentally, and read-ers are referred to the reviews by Sharma (1981)and Pay (1988), and the recommendations made atthe XIII Conference of the PermanentCommission on Foot-and-Mouth Disease of theOffice International des Epizooties (Anon., 1972),which highlighted the possible risk of spread ofFMD from sheep and goats.

The disease has a wide spectrum of clinical signs

1090-0233/99/040006 + 08 $12.00/0

Correspondence to: Dr P.V. Barnett at the above address. Tel: +44 1483 232 441; Fax: +44 1483 236 430

(Geering, 1967; Littlejohn, 1970; Sharma, 1981;Pay, 1988) which are probably influenced by thevirus strain, the breed of sheep or goat and to someextent by the environment (Geering, 1967). Thereis, however, general agreement that the disease innaturally acquired infections often takes on amilder form in small ruminants than in cattle andpigs, and in many cases may be vague. Incubation iscommonly between 3 and 8 days. Fever, anorexiaand lassitude have been observed, and lamenessoccurs in the presence or absence of foot lesions.Such lesions are in the interdigital cleft, along thecoronary bands and on the bulb of the heels. Hoofshedding sometimes happens in sheep. Orallesions are less common than on the feet and haveoften disappeared by the time foot lesions appear.When they occur, they are likely to be on the poste-rior aspects of the dorsum of the tongue ratherthan the tip, being more necrotic than vesicular, oron the dental pad. Such mouth lesions, which are

© 1999 Baillière Tindall

EPIDEMIOLOGY AND TRANSMISSION OF FMD 7

generally small, can also be distributed inside theupper lip and on the lower gums, although thesesites are rarer. Occasionally, sloughing may occur,leaving haemorrhagic ulcers. Lesions may alsooccur on the teats, vulva, prepuce and rumenalmucosa. The disease in goats can be even milder.Lameness and agalactia (Nazlioglu, 1972) are themost common signs, although some outbreakshave been recorded in which pyrexia, nasal dis-charge and salivation were observed (Pay, 1988;Shukla et al., 1974). Mouth lesions are more likelyto occur in goats (Olah et al., 1976). Mortality isoften seen in lambs and kids in the absence of anyclinical signs and is generally the result ofmyocarditis or myocardial lesions (Geering, 1967;Pay, 1988).

In some parts of the world, such as Australia,New Zealand, North America, Chile, thePatagonian region of Argentina and parts ofEurope, which have large sheep populations, FMDVcould be economically catastrophic in terms of lostproductivity, restrictions on international trade,cost of vaccination and other control measures. Theadoption by the European Union (EU) of a non-vaccination policy for the control of FMD, to allowgreater movement of livestock and their productswithin the Single Market (Directive 90/423/EEC),and increase trade with other FMD-free regions(Donaldson & Doel, 1992; Davies, 1993) also leavesthe European domestic livestock population highlysusceptible to FMD should the virus be introduced.Recent outbreaks of FMD within and around theEU (Leforban, 1996; Kitching, 1998) serve asreminders of the threat of FMD.

EPIDEMIOLOGY

Although some areas of the world with large sheepand goat populations, such as Australia, NewZealand, North America and parts of SouthAmerica, continue to remain free from FMD, thedisease is endemic or sporadic in many of the coun-tries of Asia, Africa and Eastern Europe (Kitching,1998). During the late 1980s and early 1990s anepidemic spread across North Africa from Libyaand Tunisia to Morocco. The virus, type O, isbelieved to have originated from the Middle Eastand to have had predilection for sheep (Taylor &Tufan, 1996). Outbreaks also occurred in Turkeyduring 1995 and 1996 (Kitching, 1998), in which20% of the total cases were associated with sheepand goats (Taylor & Tufan, 1996). As recently as

1996, the Balkan countries of Albania, FormerYugoslav Republic of Macedonia and FormerRepublic of Yugoslavia experienced a type A epi-demic that also involved small ruminants (Leforban,1996). A ‘stamping out’ policy was adopted and ringvaccination implemented in Albania in which a totalof 137 190 sheep and 61 101 goats were vaccinatedtogether with 59 234 cattle and 7422 pigs. In theFormer Yugoslav Republic of Macedonia, only cattlewere vaccinated.

In recent years, Great Britain and most other EUMembers have been free from FMD, the exceptionsbeing Italy, which reported 57 outbreaks in 1993,and Greece, which had epidemics in 1994 and 1996(Kitching, 1998). The 1994 Greek epidemic origi-nated from the movement of infected sheep fromthe island of Lesvos. The causal agent was a type O,similar to endemic strains in the Middle East. A totalof 95 outbreaks were finally recorded. The epidemicwas controlled by ‘stamping out’ and movementrestrictions. No evidence of a predilection of thestrain for sheep and goats (as seen in the MiddleEast) was recognised, as cattle present on affectedpremises showed high morbidity. During the courseof the outbreaks, 12 450 sheep, 4738 goats, 1241 cat-tle and 139 pigs were killed, but no vaccination wasimplemented. Thirty-nine outbreaks of FMD type Oalso occurred in Greece during 1996, probably as aconsequence of the illegal importation of live sheepfrom Turkey. Approximately 5000 sheep and goats,1800 cattle and 30 pigs were destroyed from clini-cally affected flocks/herds or following contact withinfected animals.

These outbreaks serve to demonstrate severalimportant points; firstly, the role of the Middle Eastas a reservoir of FMD, and the potential for spreadfrom the region (via Eastern Europe and countriesthat border the Mediterranean to the rest ofEurope); and secondly, the probable role of sheepand goats in disease transmission (88.4% of theregion’s livestock are small ruminants; Anon.,1993). The large number of live animal importsinto the Middle East from FMD endemic areasresults in the frequent introduction of new strainsof virus (Yadin & Cloudia, 1995). Strains that circu-lated during the 1990s seemed to have a predilec-tion for sheep and goats although they spread intothe dairy herds, in spite of regular vaccinations(Kitching, 1994). Studies in Nigeria (Obi &Newman, 1988) and South America (Fernandez A.et al., 1975; Fernandez T. et al., 1975), where com-munal farming of cattle, sheep and goats also

8 THE VETERINARY JOURNAL, 158, 1

occurs, identified a high prevalence of antibodiesagainst the virus-infection-associated (VIA) antigen(indicative of active infection with FMDV ratherthan vaccination) in sheep and goats in theabsence of clinical signs. This suggests that smallruminants have an important role in the epidemi-ology of FMD elsewhere in the world.

Owing in part to the threat to Europe posed byoutbreaks in North Africa and the Middle East, thedesire for up-to-date information on the currentdisease situation, and to establish the significanceof small ruminants in the epidemiology of FMDinfection, several recent serological surveys havebeen carried out in Morocco (Mackay, 1994;Mackay & Rendle, 1996) and Greece (Mackay et al.,1994). Ten-thousand sera samples were collectedfrom unvaccinated sheep and goats throughoutMorocco in 1992, when FMDV was widespread.Overall prevalence of infected flocks was deter-mined to be 29%. Prevalence was lower in an areawhere vaccination had taken place, suggesting thatprophylaxis had an influence in reducing thespread of disease. A further survey carried out dur-ing 1995 reported that the number of seropositiveanimals had decreased from 18.4% reported in1992 to 7.6%. Herds which practised transhu-mance or were nomadic had a higher prevalencethan fixed herds. Moreover, those herds in whichinfection had been previously recorded also gave ahigher prevalence of seropositivity (22.2% asopposed to 6.2%). Herds which had been previ-ously vaccinated (pre-November 1993) were notshown to have an increased prevalence of seroposi-tive animals, thus ruling out the possibility that theantibody detected was due to vaccination. Theseresults suggest that since the last reported case ofclinical FMD in Morocco in September 1992, FMDvirus had been persisting at a low level in theabsence of clinical disease. It is unlikely that thislow seroprevalence is either an under- or over-esti-mate of seropositive animals, as a liquid phaseblocking ELISA (Hamblin et al., 1986), a reliable,sensitive and reproducible assay (Haas, 1995), wasused throughout these surveys.

Another survey conducted in Greece during1994–95 also supports the occurrence of low-level,subclinical infection, as small clusters of sheep con-tinued to be identified as seropositive severalmonths after the last clinical case had beenreported. The killing of seropositive animals didnot prevent subsequent seroconversion of animalson the same holding. It was concluded that further

work was necessary to validate the findings of thesesurveys and establish whether seropositive flocksrepresent a real danger in terms of virus spread.Additionally, there have been several reports of ani-mals known to have been exposed to FMDV, underexperimental conditions, not seroconverting(Gibbs et al., 1975; Donaldson & Kitching, 1989).Other methods of identifying animals which havecontracted the virus and which may still be viruspositive should therefore be used, wherever possi-ble, in conjunction with serology.

The development of serological tests that reli-ably distinguish antibody produced following infec-tion from that due to vaccination together withinformation relating to the rate of spread of FMDVwithin and between flocks, which is currentlyunder investigation (P. Kitching, personal commu-nication), will greatly assist epidemiological studiesand the development of control strategies.

VIRAL PERSISTENCE

No attempts were made to recover virus from thesheep in the above serological surveys, but manyworkers have reported that the carrier state can beestablished in sheep and goats after recovery fromdisease and in vaccinated animals exposed to virus.The duration of the carrier stage in small rumi-nants, however, is shorter than that in cattle(Burrows, 1968; McVicar & Sutmoller, 1969).During the acute phase of the disease, virus is pres-ent in most tissues and organs and high quantitiesof virus are excreted. In the carrier animal, virus isrestricted to the pharyngeal area (soft palate andtonsils) and the amounts excreted are relativelyvery low. McVicar and Sutmoller (1969) demon-strated virus for up to 9 months following intranasalexposure to FMDV, and Burrows (1968) recoveredvirus from sheep oesophageal-pharyngeal (OP) flu-ids between 1–5 months post infection.

Virus recovery from carriers is often intermit-tent and of low titre (Salt, 1993). Consequently, therole of persistence in natural disease spread hasremained elusive. Some studies have reported a lowincidence of carrier sheep and goats (Garland etal., 1981; Anderson et al., 1976; Yadin & Cloudia,1995; Fondevila et al., 1996), suggesting that theseanimals play an insignificant role in disease trans-mission. On the other hand, other studies refutethis (Sharma et al., 1981; Gurhan et al., 1993;Hancock & Prado, 1993). When considering anystudies relating to persistence and the carrier state,

EPIDEMIOLOGY AND TRANSMISSION OF FMD 9

the methods of virus detection and their sensitivitymust be considered. Tissue culture techniques aresuperior to mouse inoculation methods, and cellcultures vary in their sensitivity. Bovine thyroidcells are the most sensitive cells for detectingFMDV (Straver et al., 1970; Khukhorov et al., 1973;Gurhan et al., 1993). However, successful virus iso-lation from OP samples is highly dependant oncompetent sampling, suitable storage and rapiddelivery to the laboratory, and is constrainedbecause of the presence of neutralizing antibodiesto FMDV in the sample (De Clercq et al., 1997).Alternative methods of detection, such as an anti-gen detection ELISA and/or PCR, which do notrely on live virus, may prove more useful and reli-able in establishing the extent of viral persistencein sheep and goats. A recent study by De Clercq etal. (1997) showed the advantage of an RT-PCR-ELISA in confirming the presence of FMDV inmore samples and for a longer period of time thanconventional methods.

VIRUS EXCRETION

The detection of persistent virus in sheep andgoats, however, is not enough to establish that theyare important in FMDV transmission. The route bywhich most ruminants are likely to encounterFMDV under field conditions is via the respiratorytract and therefore the amount of virus excretedinto the environment is important. Sheep andgoats have been shown to excrete similar amountsof airborne virus (Sellers & Parker, 1969;Donaldson et al., 1970). The maximal yields wereobtained from both species within a few days ofcontact exposure (Donaldson, 1979).

The amount of airborne virus excreted dependson the serotype and strain of virus involved(Donaldson et al., 1970). Sellers et al. (1977),following an experimental infection of sheep,reported that FMDV could be readily detected attwo time points after aerosol exposure to virus—firstly, between 30 min and 22 h, attributable tovirus trapped in the wool during initial exposure tovirus, and secondly between 2 and 7 days, attributa-ble to limited replication in the respiratory tract.Such virus was detectable from both susceptibleand vaccinated animals. Control of movement for2 weeks after infection was therefore recom-mended as a means of preventing disease spread.This period of production of airborne FMDV cor-responds to the period of high titres of virus iso-

lated from OP fluids identified by McVicar andSutmoller (1969). No data, however, is availablereporting the amount of virus exhaled by carriersheep and goats.

With the possible exception of an experiment byDe Clercq et al. (1997) involving two sentinel pigs,experimental transmission of FMDV from carriersto susceptible in-contacts has not been clearlydemonstrated. Since isolation of virus from the OPsamples of carrier animals is frequently intermit-tent, it is likely that a low level of virus replicationoccurs during the carrier state with occasional peri-ods of higher virus excretion. Experimental evi-dence from studies in cattle has shown a decline intitre and frequency of virus recovery throughoutthe carrier period (Rossi et al., 1988). Donaldsonand Kitching (1989) concluded that the amounts ofvirus recovered from OP fluids were generallybelow the level required for transmission of FMDVto other susceptible animals by natural routes.Woodbury (1995) concluded from experimentaland field evidence that transmission from carrier tosusceptible animals is probably a rare event, and sois most probable when there is a high ratio of sus-ceptible to carrier animals. It is therefore unlikelyto occur in areas where vaccination is practised.

In conclusion, sheep and goats are most likely tobe involved in the transmission of FMDV duringthe early stages of either clinical or subclinical FMDinfection, rather than when they are carriers, andthe period of greatest risk of transmission is up to 7days after contract with the infection.

SPECIES ADAPTATION AND VIRULENCE

When considering the role of small ruminants inthe transmission of FMDV, the virulence of FMDVstrains from sheep and goats for other hosts mustbe considered. Strains which are adapted to sheepand goats may vary in their virulence for otherspecies, such as cattle and pigs, particularly if theyhave been replicating for some time in the smallruminant host. Limited experimental evidencesuggests that this might be the case (Bauer et al.,1977). Furthermore, field cases have beenreported in which sheep and goats have been diag-nosed seropositive for FMDV in the absence of anyrecent outbreaks, and in co-existence with cattlethat have remained seronegative (Mackay, 1994;Mackay & Rendle, 1996). However, strains first iso-lated from sheep/goats have also been highly viru-lent for cattle and pigs (McVicar & Sutmoller, 1969;

10 THE VETERINARY JOURNAL, 158, 1

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Fig. 1. Serum antibody responses in sheep followingvaccination with FMDV type A22 Iraq as measured bymicroneutralization assay. Groups of three animals wereeach immunized with a 1 mL volume of vaccine (equiva-lent to a 0.5 bovine dose), adjuvanted with either (a)Al(OH)3/saponin, (b) Montanide ISA 25 or (c)Montanide ISA 206, and monitored over a 6-monthperiod.

Khukhorov et al., 1973 Yadin & Cloudia, 1995;Leforban, 1996; Kitching, 1998), and in fact the1967/68 epidemic in the UK is suspected to haveoriginated from imported contaminated frozenlamb (Anon., 1968).

VACCINATION

The role of sheep and goats in the maintenance ofFMD remains uncertain, so the design of appropri-ate disease control measures is problematical. Inparticular, it is not proven that prophylactic vacci-nation of small ruminants is essential to eradicatethe disease, and there is some evidence that FMDin sheep and goats is self-limiting (Anderson et al.,1976). Owing to the cost of vaccination, small rumi-nants tend not to be routinely vaccinated, unlessthere is an association with large numbers of cattleand swine. This is despite the recommendationthat they are included in vaccination campaignsunless it can be clearly shown to be unnecessary(Anon., 1972). When vaccination does take place,however, a conventional saponin aluminiumhydroxide, inactivated vaccine (one-third to one-quarter of the normal bovine dose) has generallybeen used, as recommended by Fontaine et al.(1966, 1969) and Pappous et al. (1972). Protectionfrom challenge (as measured by antibody responseor the absence of virus) has been shown from 21days to 6 months after vaccination (Sharma & Dutt,1968; Oral et al., 1970; Pappous et al., 1972). Morerecent studies have concentrated on vaccine for-mulations and regimes (Nair & Sen, 1992, 1993a, b;Hunter, 1996) to improve and generate long-termprotection for use in areas where FMDV is endemicor prophylactic vaccination is carried out.

Some experimental studies have indicated thatoil adjuvanted formulations give an improved anti-body response, although animals were not chal-lenged to check the protective capacity of thesevaccines (Nair & Sen, 1992; Hunter, 1996). Ourrecent studies with sheep vaccinated with A22 Iraqantigen, formulated as an oil emulsion (MontanideISA 25 or 206, Seppic) or as an aluminium hydrox-ide saponin vaccine, and monitored over a 6-month period, showed similarly rapid antibodyresponses, regardless of adjuvant, which peaked7–21 days post vaccination (Fig. 1). However, onlythe sheep vaccinated with the ISA 206 oil formula-tion maintained high titres of antibody for theduration of the trial. Further studies with theseaqueous and ISA 206 oil formulated ‘emergency’

vaccines, using other inactivated antigens, namelyO1 Lausanne, Asia 1 India and C1 Oberbayern,showed that all were able to protect sheep againstairborne homologous FMDV challenge within 4days of vaccination (Cox et al., 1999).

Volpina et al. (1996) recently reported the devel-opment of a synthetic peptide vaccine using adipalmitoyl derivative of the 135–159 fragment ofVP1 protein of the foot-and-mouth disease strainA22 which, in association with the adjuvant poly-methylsiloxane oil, was found to protect all sheep,following a single administration, for at least 7months, and 90% of the vaccinates after 1 year. Anadvantage of synthetic vaccines is their safety, asthey do not require the culture and inactivation oflive FMDV. However, as with previous studies, highlevels of peptide (2 mg/sheep) need to be adminis-tered to afford such protection.

Vaccination, particularly emergency vaccination,besides conferring protection should also reducelocal virus replication in the respiratory tract,

EPIDEMIOLOGY AND TRANSMISSION OF FMD 11

thereby dampening down the amount of virus inthe environment and reducing the risk of spread.Gibson et al. (1984) administered three- to six-folddoses of conventional aqueous vaccine to sheepand challenged the animals 1 week later by air-borne exposure. Following challenge, viraemia wasprevented but not local virus replication or excre-tion of FMDV in OP fluids. More recent studies byBarnett and Cox with emergency vaccine formula-tions have indicated that aqueous and oil formula-tions are equally efficient at reducing local virusreplication (Cox et al., 1998). Fondevila et al.(1996) concluded that vaccination in the ovinereduces infection and the probability of establish-ing the carrier state.

CONCLUSIONS

There is much circumstantial evidence to suggestthat sheep and goats may be important in the fieldtransmission of FMDV. Using more reliable, sensi-tive techniques, further studies, both during andafter field outbreaks, should be carried out to iden-tify virus carriers as well as seropositive animalswhich may or may not be infectious, in order thatthe role of each in the epidemiology of FMD can beelucidated. In the meantime, for countries whereFMD is endemic or where policies are underway toeradicate FMD, it is advisable to include sheep andgoats in the routine vaccination campaigns, partic-ularly in areas of high livestock density. Elsewhere,in FMD-free regions, strategic reserves of FMD anti-gen held in vaccine banks, such as theInternational Vaccine Bank at Pirbright, must becapable of producing formulated vaccines thatinduce rapid protection and reduce local virusreplication in both sheep and goats.

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ORAL, M., SUTCU, M., BAYRAMOGLU, O., UNLULEBLEBICI,N., EROL, N., SENTURK, M., OKAY, G., BOZ, G., ILERLE,M., YALIM, N. & GIRARD, H. C. (1970). Duration ofimmunity in sheep following foot-and-mouth diseasevaccination. FAO/AGA. EU FMD/70/5AGA/1970/7: 111–20.

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EPIDEMIOLOGY AND TRANSMISSION OF FMD 13

(Accepted for publication 1 October 1998)

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TAYLOR, M. N. & TUFAN, M. (1996). Detailed investiga-tions, using farmer interviews, to assess the lossescaused by FMD outbreaks in Turkey. Report ofTurkish-German Animal health Information Project(GTZ), Ministry of Agriculture and Rural Affairs(MARA), Republic of Turkey.

VOLPINA, O. M., YAROV, A. V., ZHMAK, M. N., KUPRIANOVA,M. A., CHEPURKIN, A. V., TOLOKNOV, A. S. & IVANOV, V.T. (1996). Synthetic vaccine against foot-and-mouth

Book Review

disease based on a palmitoyl derivative of the VP1 pro-tein 135–159 fragment of the A22 virus strain. Vaccine14, 1375–80.

WOODBURY, E. L. (1995). A review of the possible mecha-nisms for the persistence of foot-and-mouth diseasevirus. Epidemiology and Infection 114, 1–13.

YADIN, H. & CLOUDIA, K. (1995). Small ruminants as FMDvirus carriers. Report of the Session of the Research Groupof the Standing Technical Committee on Control of Foot-and-mouth Disease; pp26–32. Vladimir, Russia: Rome: FAO.

Far Away Cows: Veterinary Vignettes from the Third WorldGuilbride, P. Lewes, Sussex, The Book Guild, 1998.655 pp. £18.50 (hard) ISBN 1 85776 234 7

This would be an excellent volume to choose for DesertIsland Discs, together with the Bible. Indeed, there are per-haps surprising parallels between the two volumes for bothare, in essence, collections of books linked by a commontheme. Like parts of the Bible, Far Away Cows is aprogressive narrative that moves through time, with thestory carried by a series of anecdotes. These are, in differ-ent places, amusing, concerning, instructive, annoying oreven infuriating, as suits the point being made. Many willring bells with veterinarians who have worked in developingcountries, and it is perhaps these who will find most toempathize with in the book. However, the contrasts shouldalso be of interest to others whose experience is limited tothe developed world.

At first sight, Far Away Cows is a somewhat daunting vol-ume. It is long, perhaps overlong for a modern day autobi-ography. Nevertheless, it was sufficiently interesting tohold this reader’s attention to the end. It is the story ofa personal odyssey, the author’s 38-year-long career inveterinary medicine in tropical countries. It moves fromcolonial days in Africa, through the problems of newlyindependent Jamaica and Uganda, and on to working foran international professional civil service. Thus, it passesfrom an era in which the ‘natives’ could be termed‘Johnny Bantu’ to one in which local politicians are infirm control and can easily, for their own ends, frustrate

the best intentions of an international organisation and itsstaff. From the life of a young bachelor, it proceeds to thatof the father bringing up a large family – no less than sixdaughters and one son! – in five widely disparate coun-tries, each of which is given a distinct section, almost a‘book’ in itself. Yet the collection of ‘books’ also tells acontinuous and developing story.

The young veterinarian with which the story begins, isthrust into a remote region of Northern Rhodesia. Theinternational civil servant with which it ends, struggleswith political ideology and bureaucratic inefficiency inMarxist Mozambique. In between lies something of anidyll as a Field Officer in Jamaica, research in Uganda,high in the Andes and in the Amazonian forest of Peru,and a most frustrating time struggling to bring to birth aresearch programme in Brazil, in which local interest wasstrictly that for a potential milch cow.

There is occasional repetition and even a few howlers;that which jarred most with this helminthologist being thestatement that ‘the large white round worm’ [Toxocaravitulorum] of cattle is ‘a relation of the earthworm’!Nevertheless, having seen the same developments from avery different perspective, I would strongly recommendthis book. It is both an informative and an instructiveaccount of the achievements, despite many and variedfrustrations, of one among the many veterinarians whohave devoted their careers to the service of animals, theirowners and both local and international authorities in thedeveloping world in this century.

M.M.H. SEWELL