NADIS Parasite Forecast November 2018 Use of meteorological data to predict the prevalence of parasitic diseases

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1 SQP CPD Prgramme As part f AMTRA`s nline CPD Prgramme fr livestck SQPs, each mnth AMTRA will send yu the Parasite Frecast which will highlight the parasitic challenge facing livestck in yur area fr that mnth. At the end f the Parasite Frecast yu will find a series f multiple chice questins (quiz buttn) based n its cntents. Answer the quiz nline and yu will be ed a certificate with yur scre. This will frm part f yur SQP CPD requirement. The Parasite Frecast has been develped by NADIS (Natinal Animal Disease Infrmatin Service) and is written by leading veterinary parasitlgists and based n detailed data frm the Met Office. Merial Animal Health is cmmitted t the prvisin f up-t-date independent knwledge fr Animal Health Advisrs t enable timely and best practice advice t be given t livestck farmers. As such Merial Animal Health is prud t spnsr NADIS and the Parasite Frecast. NADIS Parasite Frecast Nvember 2018 Use f meterlgical data t predict the prevalence f parasitic diseases Reginal Weather (based n Met Office figures) Temperature: September 2018 (as C Abve/Belw Reginal Average ) Temperature: July September 2018 (as C Abve/Belw Reginal Average ) Rainfall: September 2018 (as % Abve/Belw Reginal Average ) REGIONS 0 N W Sctland 1 E Sctland 2 N E England 3 E Anglia 4 The Midlands 5 S England 6 S W Sctland 7 N W England & N Wales 8 S W England & S Wales 9 N Ireland Rainfall: July September 2018 (as % Abve/Belw Reginal Average ) The average UK temperature in September 2018 was 12.4 C, 0.2 C belw the lng-term natinal average ( ). Reginally, temperatures were similar t their respective lng-term averages in September, with cler than average cnditins experienced further nrth; Nrthern Ireland, Sctland, NW England and N Wales. Hwever, reginal temperatures fr the previus 3 mnths (July September) were still abve the lng-term average fr all regins. Ttal rainfall in September 2018 was 108% f the lng-term natinal average, althugh this varied greatly between regins, with rainfall in NW Sctland 150% f the lng-term average fr the regin, whilst Nrthern Ireland, SE England and East Anglia all experienced lwer than expected rainfall fr the mnth. Reginal rainfall fr the previus 3 mnths was belw the lng-term average acrss all regins with the exceptin f NW and SW Sctland. Nvember Parasite Frecast/Update The mst recent versin f this mnthly parasite frecast may be accessed at Supprted by Imprving sheep and cattle health

2 Liver fluke: prvisinal Autumn frecast The prvisinal fluke frecast fr Nvember 2018 is based n mnthly rainfall and temperature data frm May-September This prvisinal frecast is currently predicting Medium risk fr liver fluke in SW Sctland and Lw risk acrss all ther areas f the UK (Figure 1), althugh it shuld be nted that sme parts f western Sctland have been flagged as medium t high risk. The definitive risk frecast fr liver fluke in 2018 will be prvided in next mnth s frecast. Figure 1: Current reginal risk fr liver fluke in Autumn Remember it is imprtant t take lcal cnditins int cnsideratin when evaluating n farm risk. Whilst reginal fluke risk is lw, it is imprtant lcal factrs are taken int accunt when cnsidering n farm risk. Develpment f liver fluke and its intermediate hst, the mud snail (Galba truncatula; Figure 2) n pasture is dependent upn temperature and misture, with warm wet cnditins ptimal. On farms with permanently wet pastures and/r permanent water bdies snails may have cntinued t thrive in ht weather ver the summer, ptentially leading t high pasture infectivity in the autumn and winter mnths. Despite the verall lw predicted risk, cntinued vigilance fr signs f disease and n farm cntingency plans in the event f an utbreak are f great imprtance. Advised actins include: Mnitring fr signs f disease: Sudden death in heavy acute infectins General dullness, anaemia and shrtness f breath Rapid weight lss, fluid accumulatin Animals with chrnic infectin may shw n bvius signs f disease, yet such infectins can adversely affect prductivity by reducing fertility, grwth and milk yields. Chrnic infectin shuld be cnsidered where animals have been grazing at risk pastures. In such instances, the decisin t treat animals shuld be infrmed by diagnstic testing such as wrm egg cunts, evidence f pr bdy cnditin scre and/r sub-ptimal prductivity. Rutine diagnstic testing t give a greater insight int current infectin status: Pst-mrtem (Figure 3). Antibdy ELISAs are available fr testing individual sheep and cattle thrugh bld sampling, r t mnitr herd-level infectin status in dairy cattle thrugh testing bulk milk tank samples. A faecal antigen test is als available fr testing individual animals. Wrm egg cunts can be used t diagnse chrnic infectin in individuals, r grups f animals when using a cmpsite sample. Egg cunts cannt used fr the diagnsis f acute disease. Fr mre infrmatin n diagnstic ptins, please speak t yur vet. Figure 2: The intermediate hst f liver fluke, the mud snail (Galba truncatula), can be fund in damp, muddy areas such as the brders f pnds, streams and ditches, and in areas f bggy pasture and wet flushes. Such areas shuld therefre be cnsidered ptential surces f liver fluke infectin. Figure 3: Liver fluke infectin can be detected at pstmrtem as parasitic tracks n the liver in acute disease (left), which is cmmn in sheep in late summer and autumn. Chrnic fluke infectin may als be detected at pst-mrtem in sheep (centre) and cattle (right). Chrnic infectins may have prfund impacts n animal prductivity, yet shw very little utwards signs f disease.

3 Where fluke infectin is identified: Treatment with triclabendazle is recmmended fr acute disease, as this is the nly prduct effective against bth adult and immature stages f the parasite. With chrnic infectins, a prduct ther than triclabendazle shuld be cnsidered, as this type f disease is caused by adult fluke. It is advised t test fr treatment efficacy thrugh pre- and psttreatment diagnstic testing. Fr mre infrmatin abut treatment ptins and efficacy testing, please speak t yur vet. Risk f infectin can be reduced by identifying high risk fluke pastures and aviding grazing these during peak risk perids. Bth sheep and cattle are susceptible t infectin with liver fluke, meaning pastures previusly grazed by either species shuld be cnsidered a ptential risk t the ther. Mud snails are generally fund in damp, muddy areas (Figure 4). Outbreaks f PGE resulting frm trichstrngylsis may be seen frm late Octber nwards in stre and replacement lambs and, smetimes, yearlings (Figure 5). Risk f haemnchsis may als cntinue t be an issue. Female wrms are prlific egg-layers, meaning pastures can becme cntaminated rapidly under ptimal cnditins. As the weather becmes clder, newly acquired Haemnchus larvae will begin t encyst in the abmasal wall f the hst sheep resuming develpment in the spring if left untreated. It shuld be nted that in such infectins FECs may be negative. Figure 5: Trichstrngylsis is a cmmn prblem in stre and replacement lambs in the autumn and winter mnths It is als imprtant t cnsider the infectin status f rams pst breeding, as the cmbinatin f a high wrklad and parasite burdens may cntribute t a significant lss in bdy cnditin in these animals just ahead f winter (Figure 6). Wrm egg cunts can help t determine whether anthelmintic treatment is necessary. Figure 4: Areas f permanently wet pasture can prvide ptimal cnditins fr mud snails, and by extensin liver fluke. Large numbers f mud snails were recvered frm the wet bggy areas pictured abve, which were created by a cnstant supply f flwing surface water and paching by cattle. SHEEP Parasitic Gastrenteritis (PGE) and haemnchsis The larvae f many disease-causing rundwrm species will remain infective n grazing pastures t the end f the seasn. There have been reprts frm acrss the UK in September and Octber shwing rundwrm infectins cntinue t persist, with high wrm egg cunts and utbreaks f disease. It is therefre imprtant t maintain vigilance fr signs f disease in at risk animals grazing ptentially cntaminated pastures. Figure 6: It is imprtant t remember wrm cntrl in rams. High parasite burdens in cmbinatin with the high wrklad during tupping can have a prfund impact n health and bdy cnditin ahead f the winter mnths.

4 Advised actins include: Mnitring fr signs f disease: Signs f chrnic haemnchsis can be very similar t liver fluke infectin. If yu are in any dubt ver which parasite is causing disease, please seek veterinary advice regarding diagnsis and treatment. Cnsider wrm egg cunts and mnitring weight gain in lambs t determine infectin status and need fr treatment. Where anthelmintic treatments are required: Mve t safe pasture (eg. silage aftermath) after treatment if available. Leave animals n dirty pasture fr 2-3 days prir t mving. Aim t leave at least 10% f the flck untreated Check efficacy thrugh wrm egg cunts: Re-test individuals at 7-14 days pst treatment depending upn the prduct used. CATTLE Dsing at husing Husing presents an pprtunity in the nging cntrl f parasitic disease n farm. Wrm burdens acquired ver the grazing seasn may be targeted effectively at this time withut risk f animals becming re-infected. There are als benefits n grwth and feed efficiency assciated with treating cattle fr fluke at husing. As is the case during the grazing seasn, any treatments administered shuld be based n evidence f infectin, such as clinical disease and/r diagnstic testing (e.g. wrm egg cunts). Treatment efficacy shuld als be cnsidered at this time since ineffective treatments may result in a cntinued parasitic burden (with assciated reductins in prductivity) and ptential pasture cntaminatin with resistant parasites at turn-ut the fllwing grazing seasn. Fr grwing cattle hused after their first r secnd seasn treatment with prducts cntaining either a Grup 3-ML r Grup 1-BZ anthelmintic is recmmended at husing. These prducts are effective against encysted stage larvae acquired in the latter stages f the grazing seasn. If untreated, heavy burdens f encysted larvae can cause type-2 stertagisis in later winter r the fllwing year due t triggered mass emergence. Encysted wrm burdens cannt be assessed by wrm egg cunt. Whilst husing effectively eliminates risk f infectin with pasture assciated parasites such as intestinal rundwrms and flukes, risk f luse infestatins may increase at this time since these parasites can spread directly frm animal t animal very easily nce they are penned in clse prximity t ne anther in what are relatively dry, warm cnditins. Grup 3-ML pur-n preparatins have the added advantage they are als effective against bth sucking and chewing lice (Figure 7). Cattle expsed t liver fluke infectin can either be dsed with a prduct cntaining triclabendazle at husing, r use an alternative prduct at a delayed interval pst-husing. Prvided levels f infectin are nt t severe, the latter ptin is mre desirable in the cntext f drug resistance, since it allws triclabendazle t be used mre sparingly, preserving its efficacy n farm fr when it is mst needed (i.e. in acute clinical disease). If using a prduct ther than triclabendazle it will be necessary t either repeat r delay treatment s that all flukes are f a sufficient age fr the drugs t be fully effective. Fr example, if treating with clsantel COWS recmmend delaying treatment fr 6-7 weeks pst-husing befre treating, r treating at husing then testing 6-7 weeks later t determine whether a secnd treatment is needed. Sme f these alternative prducts, such as albendazle, xyclzanide als have the added benefit f being licenced fr use in lactating animals prvided milk withhld perids are bserved. It is imprtant t check labelling f individual prducts. Whichever prduct is ultimately used, cattle shuld be tested later in the husing perid t assess treatment efficacy. Fr mre infrmatin please speak t yur vet, r visit the COWS website. Figure 7: Pur-n preparatins f 3-ML wrmers are als effective in cntrlling sucking and chewing lice.

5 Dn t frget t try the interactive quiz Lcal farm cnditins may vary s cnsult yur veterinary surgen. Parasite cntrl shuld be part f yur veterinary health plan. T watch a webinar (vide) based n this article and take an electrnic quiz wrth 3 CPD pints, click WEBINAR. NADIS seeks t ensure that the infrmatin cntained within this dcument is accurate at the time f printing. Hwever, subject t the peratin f law NADIS accepts n liability fr lss, damage r injury hwsever caused r suffered directly r indirectly in relatin t infrmatin and pinins cntained in r mitted frm this dcument. T see the full range f NADIS livestck health bulletins please visit