NADIS Parasite Forecast November 2017 Use of meteorological data to predict the prevalence of parasitic diseases

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Cecilia Paul
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SQP CPD Programme As part of AMTRA`s online CPD Programme for livestock SQPs, each month AMTRA will send you the Parasite Forecast which will highlight the parasitic challenge facing livestock in

Answer the quiz online and you will be emailed a certificate with your score. This will form part of your SQP CPD requirement.

Merial Animal Health is committed to the provision of up-to-date independent knowledge for Animal Health Advisors to enable timely and best practice advice to be given to livestock farmers.

1 SQP CPD Programme As part of AMTRA`s online CPD Programme for livestock SQPs, each month AMTRA will send you the Parasite Forecast which will highlight the parasitic challenge facing livestock in your area for that month. At the end of the Parasite Forecast you will find a series of multiple choice questions (quiz button) based on its contents. Answer the quiz online and you will be ed a certificate with your score. This will form part of your SQP CPD requirement. The Parasite Forecast has been developed by NADIS (National Animal Disease Information Service) and is written by leading veterinary parasitologists and based on detailed data from the Met Office. Merial Animal Health is committed to the provision of up-to-date independent knowledge for Animal Health Advisors to enable timely and best practice advice to be given to livestock farmers. As such Merial Animal Health is proud to sponsor NADIS and the Parasite Forecast. NADIS Parasite Forecast November 2017 Use of meteorological data to predict the prevalence of parasitic diseases Regional Weather (based on Met Office figures) Temperature: September 2017 (as C Above/Below Regional Average ) Temperature: July - September 2017 (as C Above/Below Regional Average ) Rainfall: September 2017 (as % Above/Below Regional Average ) REGIONS 0 N W Scotland 1 E Scotland 2 N E England 3 E Anglia 4 The Midlands 5 S England 6 S W Scotland 7 N W England & N Wales 8 S W England & S Wales 9 N Ireland Rainfall: July September 2017 (as % Above/Below Regional Average ) September started off dry and sunny in many parts of Britain, but the rest of the month was unsettled, with an unusually high number of rain days across England. The UK mean temperature was 0.1 C below the long-term average of 12.6 C for the month. Rainfall was mostly above normal except in parts of SE England and NW Scotland, with over double the average amount in the extreme SE of England. November Parasite Forecast/Update The most recent version of this monthly parasite forecast may be accessed at Supported by Improving sheep and cattle health

Liver Fluke Forecast The updated regional fluke forecast, based on rainfall to the end of September, indicates the potential for a high-risk of fluke infection in North and West Scotland and South

Fluke risk map The situation may change depending on rainfall in October and the final regional fluke-risk forecast will be issued next month.

areas of Western Scotland, and North Wales were at high-risk.

young immature fluke stages. A second treatment with TCBZ is likely to be necessary in parts of Scotland and South Wales where there remains a very high liver fluke disease risk.

2 Liver Fluke Forecast The updated regional fluke forecast, based on rainfall to the end of September, indicates the potential for a high-risk of fluke infection in North and West Scotland and South Wales this autumn; and medium-risk in the Scottish borders, North Wales and parts of NW and SW England. Central and eastern regions of England are currently forecast to be at low-risk. Fluke risk map The situation may change depending on rainfall in October and the final regional fluke-risk forecast will be issued next month. An earlier forecast for acute fluke disease issued with the September forecast, and based on regional weather data in August to October last year, and May and June this year, predicted that localised areas of Western Scotland, and North Wales were at high-risk. SHEEP Fluke The recommendations for liver fluke treatments for November/December are: Triclabendazole (TCBZ) is the drug of choice in cases of acute fluke disease because it is effective against very young immature fluke stages. A second treatment with TCBZ is likely to be necessary in parts of Scotland and South Wales where there remains a very high liver fluke disease risk. Where TCBZ- resistance is suspected, treatments from November onwards could include either closantel or nitroxynil, which are active on later immature (> 6-7week-old) and adult fluke. Fluke faecal egg count reduction tests to detect TCBZ- resistance are unreliable in acute fluke infections as eggs don t start to appear in faeces until weeks post-infection. Instead, the coproantigen ELISA test can be used two to three weeks after dosing and farmers should contact their veterinary practitioner for further advice where such drug resistance is suspected. Farmers in other regions of the UK should consult their veterinary surgeon about fluke treatment as action may be necessary during November if treatment has not already been given. Signs of Acute Fluke Disease Sheep with acute fluke infestation, in which there are large numbers of immature flukes, may simply be found dead without prior signs of illness therefore it is important to have all sudden deaths investigated to allow immediate preventive measures. Post-mortem examination is essential to establish a diagnosis of acute fluke. Less severe clinical signs include reduced grazing, rapid weight loss, weakness, abdominal pain and anaemia. Less severe clinical signs of subacute liver fluke diseases include rapid weight loss, abdominal pain, and anaemia. As well as the regional fluke forecast, more local NADIS forecasts will be produced in November. More detailed information will be made available through veterinary practices.

Anaemia (pale mucous membranes) caused by liver fluke disease Parasitic gastroenteritis (PGE) Prolonged wet and mild weather will give rise to flushes of infective

Heavy infestations cause black foetid diarrhoea (black scour) and rapid weight loss.

conditions. With reports of sporadic cases this autumn, look out for affected sheep showing clinical signs similar to acute fluke, including sudden death.

As the weather becomes colder, most acquired Haemonchus larvae will inhibit in the abomasal wall of the host sheep resuming development in the spring if left

Trichostrongylosis can also affect gimmers in late autumn/winter Consult your veterinary surgeon about wormer choice before moving fattening lambs onto catch crops.

3 Anaemia (pale mucous membranes) caused by liver fluke disease Parasitic gastroenteritis (PGE) Prolonged wet and mild weather will give rise to flushes of infective worm larvae on pastures. Outbreaks of trichostrongylosis are often seen from late October onwards in store and replacement lambs, and sometimes yearlings. Heavy infestations cause black foetid diarrhoea (black scour) and rapid weight loss. Sudden outbreaks of haemonchosis can occur as the female worms are prolific egg-layers, resulting in high FEC and rapid pasture contamination under optimal conditions. With reports of sporadic cases this autumn, look out for affected sheep showing clinical signs similar to acute fluke, including sudden death. Monitor lamb liveweight gain (LWG) or worm faecal egg counts (FEC) to determine the need for anthelmintic treatments. As the weather becomes colder, most acquired Haemonchus larvae will inhibit in the abomasal wall of the host sheep resuming development in the spring if left untreated but note that arrested larvae do not produce eggs so FECs may be negative. Trichostrongylosis can also affect gimmers in late autumn/winter Consult your veterinary surgeon about wormer choice before moving fattening lambs onto catch crops. Anthelmintic treatments post-tupping A faecal worm egg count will decide whether anthelmintic treatment is necessary in rams after mating; marked condition loss may compound parasite problems. Trichostrongylosis is often seen in late autumn/winter in store and replacement lambs This ram has lost a great deal of condition over a 7-week mating period. Worm FEC will decide whether rams require worming after tupping

Cattle Fluke Outdoor grazing cattle in high-risk areas may need to be dosed for fluke with a product with activity against immature fluke and moved onto fluke-free pastures as soon as possible after

4 Cattle Fluke Outdoor grazing cattle in high-risk areas may need to be dosed for fluke with a product with activity against immature fluke and moved onto fluke-free pastures as soon as possible after treatment to avoid re-infection. Whilst triclabendazole is the most effective against early immature fluke, because acute fluke is rare in cattle, an alternative product may be appropriate, so seek advice and base treatments on local farm conditions and the NADIS fluke forecast. Housed cattle exposed to liver fluke infection should be dosed either at housing, or at a delayed interval post-housing, as not all products are active against early immature stages of fluke. Choice of product will also be influenced by factors such as meat or milk withdrawal periods, risks posed by other parasites, and ease of administration. Cattle dosed on housing, should be tested later in the housing period for the presence of adult fluke, or given a second treatment to ensure all fluke are removed. Alternatively, if using products containing closantel or nitroxynil then consider delaying treatment for 6-7 weeks; or with oxyclozanide or albendazole delay weeks, as the majority of fluke will then be susceptible to treatment. When using combination products such as closantel and ivermectin, the timing of treatment must relate to closantel as treatment at housing may be ineffective against any early stage flukes present. Very few products can be used in dairy cattle, and veterinary advice should be sort for treatments at drying off and only considered if there is evidence of fluke infection in the herd. Only products containing oxyclozanide or albendazole can be used in lactating cows, providing milk withholding periods are observed, so it is important to check labelling on individual products A bulk milk tank ELISA to monitor herd exposure to fluke and efficacy of control programmes is available. WORMS Growing cattle housed after their first or second season at pasture should be treated with products containing either a Group 3-ML or Group 1-BZ anthelmintic at housing, which are effective against inhibited worm larvae. Group 3-ML pour-on preparations have the added advantage they are also effective against both sucking and chewing lice. Severe liver fluke infestation. Treatment of housed cattle may need to be repeated or delayed after housing to ensure all flukes are removed Don t forget to try the interactive quiz Local farm conditions may vary so consult your veterinary surgeon. Parasite control should be part of your veterinary health plan. To watch a webinar (video) based on this article and take an electronic quiz worth 3 CPD points, click WEBINAR. Supporting Knowledge Transfer NADIS seeks to ensure that the information contained within this document is accurate at the time of printing. However, subject to the operation of law NADIS accepts no liability for loss, damage or injury howsoever caused or suffered directly or indirectly in relation to information and opinions contained in or omitted from this document. To see the full range of NADIS livestock health bulletins please visit

5 Copyright NADIS 2017

NADIS Parasite Forecast Webinar: October 2018

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