1

GB small ruminant quarterly report

Disease surveillance and emerging threats

Volume 22: Q4 – October - December 2019

Highlights

Footvax vaccination reaction in a ewe – page 4

Cobalt deficiency - Pine in lambs – page 13

Listeriosis in goats – page 16

Contents

Introduction and overview .................................................................................................... 2

New and re-emerging diseases and threats ........................................................................ 4

Unusual diagnoses .............................................................................................................. 4

Changes in disease patterns and risk factors ...................................................................... 5

Centre of Expertise for Extensively Managed Livestock .................................................... 19

Horizon scanning ............................................................................................................... 22

Publications ....................................................................................................................... 24

Editor: Amanda Carson, APHA Penrith Phone: + 44 (0) 7909532229

Email: Amanda.carson@apha.gov.uk

2

Introduction and overview

This quarterly report reviews disease trends and disease threats for the fourth quarter of

2019, October to December. It contains analyses carried out on disease data gathered

from APHA, SRUC Veterinary Services division of Scotland’s Rural College (SRUC) and

partner post mortem providers and intelligence gathered through the Small Ruminant

Species Expert networks. In addition, links to other sources of information including reports

from other parts of the APHA and Defra agencies are included. A full explanation of how

data is analysed is provided in the annexe available on GOV.UK

https://www.gov.uk/government/publications/information-on-data-analysis

Issues & Trends

Weather

The jet stream regularly tracked further south than usual, meaning that much of England

and Wales were wetter and duller than average for October and November. In November

2019, Yorkshire and the Humber, East Midlands, West Midlands, Gloucestershire were

affected by serious river and surface water flooding. APHA published a document on the

risks associated with pasture/farmland which has been flooded.

http://apha.defra.gov.uk/documents/surveillance/apha-flood-guidance-post-flooding.pdf

A new study (https://iopscience.iop.org/article/10.1088/1748-9326/ab492b) led by

the University of Exeter – using climate projection data from the Met Office – is suggesting

that unchecked climate change could create a significant impact on farming in Great

Britain, helping to redraw the agricultural map: driving Britain’s arable farming north and

west, and potentially leaving the east and south-east unable to support crop growing.

NADIS parasite forecasts reported: “Despite the relatively mild weather experienced in

November and December, development and emergence of liver fluke on pastures is likely

to have arrested at this time, since development of the free-living stages of liver fluke and

its intermediate snail host require average temperatures at or above 10oC. However,

previously contaminated pastures will remain infective over winter and into the following

season, meaning continued vigilance for signs of disease in animals grazing “fluky”

pastures (areas of wet/boggy grazing and those adjacent to permanent water bodies) is

necessary”.

You can subscribe to NADIS to receive their parasite forecasts:

https://www.nadis.org.uk/parasite-forecast/

3

Industry

Lamb prices rose ahead of the usual seasonal trend during the fourth quarter of 2019. The

increasing cost and declining availability of international imports has provided support to

the market. Farmgate lamb prices in New Zealand and Australia have been above GB

levels since the summer, reflecting tightening supplies and strong import demand from

China. As global supplies are diverted away from Europe towards Asia, this has created

opportunities for British lamb. Nonetheless, exports during Q4 were back 5% on the year,

probably influenced by limited product availability as imports dropped by 13%. Sheep meat

production was higher in Q4 though, with an increase in both throughput and carcase

weights, reaching 84,000 tonnes. This was 2% higher than Q4 the year before. Despite

strong global market drivers, British retail demand remains a challenging area of the

market. Consumer purchases of fresh/frozen lamb were down 5% in the twelve weeks

leading to 29 December. However, this decline has not dampened lamb prices. Moving

into 2020, prices have continued to increase and remain at unusually high levels.

Bethan Wilkins AHDB

Figure 1: Autumn 2019 mean temperature anomaly compared to 1981-2010 expressed as degree difference

from the average for 1981-2010 (left) and actual rainfall amount % of average 1981 -2010 (right)

4

New and re-emerging diseases and threats

Unusual diagnoses

Compressive cervical myelopathy of Texel sheep

Further cases of compressive cervical myelopathy of Texel sheep or “wobbler syndrome”

were diagnosed this quarter (an earlier case was described in the Q2 2019 report). On this

occasion diagnoses were made in three different animals submitted to APAH Shrewsbury

Veterinary Investigation Centre (VIC). All were Texel rams; one was a lamb, the other two

were shearlings. Intermittent ataxia had been reported in the shearling rams which

commenced a year prior to submission. The ram lamb was noted to stagger on the

forelegs prior to becoming recumbent. No cranial nerve deficits were noted on clinical

examination.

On post-mortem examination excessive fat was noted throughout the carcases of the all

three animals. No other significant gross abnormalities were identified in the shearling

rams. In the ram lamb there was an area of reddening of the sub-dura at the level of C6.

Following removal of the spinal cord close inspection revealed distinct narrowing of the

cord at this level.

Histopathology identified axonal degeneration which was more severe in the peripheral

white matter, confirming chronic spinal cord compression in all three sheep, resulting in

loss of ventral motor neurones and nerve roots. This condition has previously been

described (Penny and others 2007) and continues to be identified by APHA sporadically.

To date the aetiology and pathogenesis have not been fully elucidated.

Footrot vaccination reaction in a ewe

A six-year old mule ewe was submitted for postmortem examination to investigate the

cause of malaise, diarrhoea, melena and death. Five ewes in a group of 65 had been

affected, with one being found dead (PME by private vet), the submitted ewe was

recumbent and tremors, and at least three others were dull and inappetant. The ewes had

been vaccinated with footrot vaccine on the right side of the neck, and given a trace

element bolus, six days prior to submission. They had been vaccinated with the same

vaccine on the left side of the neck the previous year, and it was reported that some ewes

had a firm swelling on the left neck. Postmortem examination revealed an abscess on the

left neck adjacent to the cranial cervical vertebrae (Figure 2), and swelling of the muscle in

the ventral right neck. There was fibrino-purulent material around the spinal cord in the

area adjacent to the abscess (Figure 3) A severe haemorrhagic enteritis was also present

(Figure 4). No significant bacterial pathogens were isolated, and no clostridial toxins were

detected. Liver copper levels were within reference range. The most likely explanation for

the clinical signs and postmortem findings was a ‘reactivation’ of the previous year’s

vaccine reaction, and infection tracking around the spinal cord. The enteritis seen in both

5

necropsies may have been ‘shock-gut’ in response to the vaccine reaction and infection.

The histopathology of the right neck muscle and the lymph node were unremarkable. The

case was reported to the VMD by the private vet as a suspect adverse reaction, and a

review of vaccination technique was undertaken.

Figure 4: Haemorrhagic enteritis

Changes in disease patterns and risk factors

Syndromic analysis

Most common diagnoses Q4 2019

During Q4 2019, 949 VIDA coded diagnostic submissions were received in GB.

Figure 2: Abscess adjacent to the cervical vertebrae Figure 3: Fibrinous material around the spinal cord

6

During Q4 the presenting signs of sheep and age category from which samples/carcases

were submitted are shown here, with wasting and found dead the most common signs

(Figure 5) and age group for submissions (Figure 6).

During Q4 2019 for sheep with presenting sign found dead the 10 most common VIDA diagnoses made (Figure 7) and age group of sheep (Figure 8) are shown.

During Q4 2019 the 10 most common VIDA diagnoses (Figure 9) and age group of sheep (Figure 10) with presenting sign “wasting” are shown.

Age Group Submissions

Adult 300

Mixed 14

Neonatal 7

Post wean 301

Prewean 16

Unknown/other 311

Figure 6: Age group of submissions Q4 2019

Age Group Submissions

Adult 57

Neonatal 1

Post wean 91

Prewean 4

unknown/other 53

Figure 8: Age group of submissions

with presenting sign found dead

273

206

84

76

68

54

37

36

36

31

14

13

11

10

WASTING

FOUNDDEAD

DIARRHOEA & GIT

SKIN

UNKNOWN

NERVOUS

MALAISE

RESPIR

Others

ABORTION

RECUMBENT

REPRO

LAME & MUSC_SKEL

EYE

20 19

11 11 11

8 7 7 6 6

Figure 5: Presenting signs of sheep from GB submissions Oct – Dec 2019

Figure 7: Top 10 GB VIDA diagnoses for sheep Oct – Dec 2019 with presenting

sign found dead

7

Syndromic alerts were raised this quarter for the following diseases:

Pine/Cobalt deficiency, Hyposelenosis, Clostridium perfringens D infection, PGE –

Haemonchosis, Parasitic pneumonia, Sheep Scab - Psoroptes ovis,

Parasitology

Parasitic Gastroenteritis (PGE)

During the Q4 period diagnoses of PGE in lambs are common, and in Q4 2019 appear

reduced but not significantly different from the previous year (Figure 11). PGE was also

found together with trace element deficiencies and in a small number of cases, Anaplasma

phagocytophilum (tick borne fever).

Age Group Submissions

Adult 82

Mixed 3

Post wean 76

Prewean 7

Unknown/other 105

Figure 10: Age group of submissions with

presenting sign wasting

39

24

17 16

6 6 5 5 4 4

05

1015202530354045

Figure 9: Top 10 GB VIDA diagnoses for sheep Oct – Dec 2019 with

presenting sign wasting

8

Figure 11: GB Incidents of PGE for Q4 as a % of diagnosable submissions 2007-2019

PGE-Haemonchosis

PGE Haemonchosis was reported in 30 submissions in 2019, peaking in quarter three

(Figure 12), but was still being diagnosed in quarter 4, in both adults and lambs.

Haemonchus contortus larvae can survive warmer temperatures on pasture longer than

other nematodes, so the warmer temperatures seen in the last couple of years could have

influenced this. Cases were diagnosed in all areas of GB more commonly in lowland

sheep, but also some in hill/upland flocks.

Figure 12: Seasonal GB incidents of PGE Haemonchosis in sheep as a percentage of diagnosable submissions

Liver Fluke

The final quarter of 2019 sees the incidence of both acute and chronic liver fluke remaining

well below the incidence diagnosed as a percentage of diagnostic submissions for the

previous 15 years. With the incidence of acute fluke being similar across England, Wales

and Scotland (Figure 13).

9

Figure 13: GB Incidents of Acute Fluke for Q4 as a % of diagnosable submissions 2004-2019

The incidence of chronic fluke was higher in Scotland than England and Wales, but also

still well below the previous years (Figure 14).

Figure 14: GB Incidents of Chronic Fluke for Q4 as a % of diagnosable submissions 2004-2019

On examination of abattoir data for the last three years a similar reduction in numbers of

affected livers seen at meat inspection is revealed. The chart below show the recorded

incidence of chronic fluke disease (assessed as a fibrotic liver with adult fluke in bile

ducts), as a percentage of throughput. An upward increase in incidence of chronic

disease, as the quarter has progressed, can be seen from the abattoir data but reducing

during 2019 compared to 2018 & 2017 (Figure 15).

10

Figure 15: Chronic Liver fluke recorded by abattoirs in England and Wales Q4 2017 – 2019 expressed as a % of

throughput

This data are separated into England and Wales but cannot be taken to represent where in

the country disease occurred, since the geographical region refers to the abattoir location,

not from where the sheep originated.

Wet summers can influence the incidence of liver fluke as seen in 2012. However, the

incidence of fluke in 2020 might increase as the warm and wetter weather experienced for

the last six months of the year will have favoured survival of both the infective

metacercariae and the intermediate host, the mud snail and farmers need to be alert to the

potential of a rise in cases.

Sheep Scab

Sheep scab is a form of allergic dermatitis caused by infestation of the skin surface with

the scab mite Psoroptes ovis.

Sheep scab was the most common skin VIDA diagnosis in 2019. In 2019 the 53% of the

skin diseases diagnosed were caused by Psoroptes ovis. Sheep scab is primarily

considered a winter disease with most cases occurring between October and April

(Figure 16). This disease was diagnosed on 35 submissions during the fourth quarter of

2019. ORF/contagious pustular dermatitis was the second most common skin disease

detected in sheep in 2019.

0

1

2

3

4

5

6

7

8

9

oct 17 oct 18 oct 19 nov 17 nov 18 nov 19 dec 17 dec 18 dec 19

Mature fluke

England Wales

11

Figure 16: Seasonal distribution of Sheep scab from VIDA diagnoses 2004 -2019

In 2017 and 2018 APHA scanning surveillance identified cases where sheep affected by

sheep scab mites (Psoroptes ovis) that had not responded to treatments for scab with an

injectable product containing the active ingredient, a macrocyclic lactone (ML), moxidectin.

This year resistance to all three available ML compounds in populations of Psoroptes

mites was demonstrated in the UK (Sturgess-Osborne and others 2019). To date, most of

the resistant P. ovis populations that have been detected were located in Wales and

English counties adjacent to the Welsh border.

APHA is keen to investigate cases of flocks that do not appear to be responding to ML

treatment to sheep scab to determine how widespread resistance is.

Enteric disease

Clostridium Perfringens Type D

The number of incidents diagnosed with Pulpy Kidney, remained at a high level for this

quarter (Figure 17). Twenty cases have been diagnosed with this condition in GB during

Q4, compared to 22 for the equivalent quarter in 2018. Outbreaks are associated with

sudden change in diet, such as introduction of creep feed for sucking lambs or concentrate

feed to fatten older lambs. The disease is best prevented by vaccination.

0%

5%

10%

15%

20%

25%

Distribution of sheep scab over the year

12

Figure 17: GB Incidents of Clostridium perfringens D Q4, as a % of diagnosable submissions 2007-2019

Johne’s disease

The percentage of submissions diagnosed with Johne’s disease has increased, compared

to previous years and it remains one of the common and important conditions diagnosed in

sheep (Figure 18). The most common presenting clinical signs are wasting and diarrhoea

(Figure 19).

Figure 18: GB Incidents of Johne’s disease Q4, as a % of diagnosable submissions 2007-2019

13

Figure 19: Presenting clinical signs of sheep cases, diagnosed with Johne’s disease 2002 – 2019 in GB

Metabolic disease

Cobalt deficiency - Pine in lambs

The incidence of cobalt deficiency had significantly increased in GB Q4 2019 compared to

Q4 2018, from 2.7% of submission tested in 2018, to 9.9% of submissions tested in Q4

2019 (Figure 20).

14

Figure 20: Incidents of cobalt deficiency in sheep as % of diagnosable submissions 2015 -2019 by

country

Cobalt deficiency was confirmed in a 6-month-old Suffolk x Mule lamb from a group of 400

in which at least 10% looked poor and weak. The lamb had shown lateral recumbency and

mild opisthotonus, with intermittent nystagmus, before euthanasia, as well as scab

covered ears. A heavy worm burden was identified (13,150 epg) and vitamin B12 testing

confirmed cobalt deficiency (<111 µmol/l, reference >221). Pine had been suspected

because, in addition to the scabby ears, the liver was very pale and friable which was

grossly suggestive of “Ovine white liver disease”. The large and ongoing worm burden is

likely to have contributed to the deficiency due to maldigestion and malabsorption, as the

abomasum showed nodular thickening typical of ostertagiasis.

Hyposelenosis in sheep

The most common presenting sign for sheep diagnosed with hyposelenosis was wasting

(43.6% of diagnosed cases). The carcase submissions for which this was diagnosed

generally had other diseases detected. The commonest concomitant diseases were cobalt

deficiency (36% of cases), parasitic gastroenteritis (25.6% of cases) and pneumonia (15%

of cases). Some of these sheep had more than two diseases diagnosed.

Two five-month-old lambs submitted to investigate malaise, wasting, diarrhoea and

sudden death were also diagnosed with parasitic gastroenteritis (PGE), cobalt pine and

hyposelenosis. Four lambs in a group of 100 had died, but others were in poor condition.

The lambs were pale, with small and pale livers, and crusting on the skin of the ears.

Gross pathology also indicated enteritis. Both lambs had high Trichostrongyle-type faecal

egg counts (6000 and 3850), and heavy infestations of Teladorsagia on the total worm

count (11,000 and 17.500). Liver cobalt levels were 0.04 mg/kg DM in both (ref range

>0.06), indicating cobalt pine. Liver selenium was 0.26 mg/kg DM in both (ref range 0.9-

3.5) indicating hyposelenosis. These deficiencies could have predisposed to PGE, and

been exacerbated by the PGE.

0.00%

2.00%

4.00%

6.00%

8.00%

10.00%

12.00%

14.00%

2015 2016 2017 2018 2019

E&W Scot GB

15

Malnutrition

Submissions this quarter included situations where concentrate feed had been introduced,

or the quantity increased, too quickly; in response to the poor condition of the lambs, and

this had resulted in ruminal acidosis.

Ruminal acidosis and bloat following introduction of concentrate feed

One lamb was submitted to investigate malaise and sudden death. Four five-month-old

lambs in a group of 60 had died over 24 hours, and others were lethargic and inappetant.

The lambs had been outdoors, but had been brought inside and fed on silage and

concentrates for the ten days prior to submission. Postmortem examination revealed

ruminal bloat, ruminal acidosis, pneumonia and enteritis. There was an oesophageal bloat

line and the rumen pH was 5.0.Total worm counts were 1200 Teladorsagia spp and 3700

Nematodirus battus. Lung histopathology was suggestive of Pasteurella pneumonia.

Acute parasitic gastroenteritis and ruminal acidosis

Three seven-month-old lambs were submitted to investigate sudden death. The farm has

630 lambs out at grass, and 15 had been found dead over the week prior to submission.

The lambs had also been drenched with a benzimidazole wormer twice over the summer,

with a levamisole wormer later in the summer, and with a macrocyclic lactone wormer six

weeks prior to submission. The lambs had been given haylage, barley and protein pellets

(with minerals) since weaning, in addition to the grass. At the time of submission they were

on ad-lib barley and protein pellets in a bulk hopper. One of the lambs had a large quantity

of whole cereal grains in the rumen and the rumen pH was 5.0. All three lambs had watery

intestinal contents and faeces, and whipworm detected in the caecum. The faecal egg

counts indicated low to moderate infestations, but the total worm counts indicated very

heavy worm burdens suggesting a review of parasite control was required.

Ruminal acidosis following movement to a stubble field

A six-month-old Suffolk cross lamb was submitted to SRUC Perth Disease Surveillance

Centre for postmortem examination, after several lambs were found dead in the three

week period after the group were moved to a barley stubble field. A large quantity of

cereal grains was found within the rumen, and a rumen content pH of 4 confirmed ruminal

acidosis as the cause of death.

Nervous disease

Louping ill

Q4 diagnoses of Louping ill remained static when comparing 2018 and 2019 data;

however, examination of the annual figures showed an overall increase in cases reported

across GB this year when compared to 2018 (Figure 21);16 cases (1.02%) were recorded

16

in 2019 compared to 13 (0.62%) recorded in 2018. Increased cases were seen by both

APHA and SAC. As discussed in previous quarterly reports it is not unusual to see yearly

fluctuations in Louping ill cases as tick activity is strongly correlated with climatic

conditions.

Figure 21: GB Annual Incidents of Chronic Fluke as a % of diagnosable submissions 2007-2019

Cerebro-cortical necrosis (CCN)

There was an increase in the diagnoses of CCN this quarter with 7 (2.36%) incidents

reported in 2019 compared to 3 (0.71%) in 2018. Increases were seen by both APHA and

SRUC VS.

This trend was mirrored in the annual data with an increase in total GB diagnoses for the

year. This increase in diagnoses was seen across both APHA and SRUC VS (Figure 22).

Figure 22: GB Annual Incidents of CCN in sheep as a % of diagnosable submissions 2007-2019

Listeriosis in goats

Meningoencephalitis due to infection with Listeria monocytogenes was diagnosed by

APHA Penrith VIC in a five-year-old cross-bred billy goat which was originally in a group of

nine goats on a smallholding. Over a period of eleven months five goats had presented

with acute neurological signs at random intervals. The first four affected goats were adults.

They were treated for suspect listeriosis, but all died. The goats had access to housing,

straw bedded and outdoors. They were fed on hay / haylage and a proprietary goat feed.

17

The goats were not vaccinated. There was no concern about access to lead or any other

toxin. A billy goat presented with similar signs: acute onset ataxia, hyper salivation,

excessive lacrimation, negative pupillary light response, blindness, vocalisation, apparent

pain, reduced rumen motility and pyrexia (40.5° C). This goat was not treated and was

euthanased with barbiturate injection. On postmortem examination there were slightly

cloudy meninges and slight symmetrical brain auto fluorescence which was only evident at

the surface of the brain. The brain was anatomically normal and there was very little gross

pathology within the carcase. L. monocytogenes was detected in direct cultures of the

brain. Histopathological examination of the brain revealed a severe multifocal chronic

active lymphoplasmacytic, necrotising and suppurative meningoencephalitis which was

consistent with a diagnosis of listeriosis.

APHA Thirsk VIC also diagnosed listeriosis in two adult goats from a herd of 52 goats. The

initial sign was salivation/drooling, and then the signs progressed to weakness and ataxia,

and then recumbency and teeth grinding. All goats were on the same feed of silage,

crushed wheat and brewer’s grain. No management changes were reported. The goats

had been wormed two months prior to submission, they had not received any other

medication prior to illness and were not vaccinated. Brain histopathology of both goats was

consistent with listeriosis.

Listeriosis is usually an ascending neural infection, originating in the oral cavity, via the

trigeminal nerve. It is often associated with tooth eruption and the feeding of silage with a

high listerial count. It can also be seen with oral lesions (which may have healed at the

time of postmortem examination, as the incubation period is a few weeks). L.

monocytogenes is an environmental organism - potential risk factors would also include

browsing thorny shrubs / plants; lesions caused by poorly maintained drench guns / poor

drenching technique; contaminated troughs; poor dentition; bare paddocks / soil exposure;

and the feeding of root crops. The seasonal distribution of listeriosis in goats is shown in

Figure 23. Advice was also provided on potential zoonotic risk.

Figure 23: Seasonal distribution of GB VIDA diagnoses for Listeriosis in goats 2002 - 2019

Respiratory disease

Parasitic pneumonia

Parasitic pneumonia numbers were raised to 3.17% of diagnosable submissions Q4 2019,

from 2.11% recorded during Q4 in 2018 (Figure 24). In both quarters however there were

98

13

6

12

79

3 34

10 10

jan feb mar apr may jun jul aug sep oct nov dec

18

10 diagnoses made. The diagnostic rate during this quarter is typically between 0.64 and

1.96% of diagnosable submissions. The increase was due to increased numbers of cases

in post weaned lambs in England and Wales. I t should also be noted that the newer

wormer (monepantel) does not kill Dictyocaulus filariae.

Figure 24: GB Incidents of Pneumonia – parasitic in sheep Q4, as a % of diagnosable submissions 2007-2019

Pneumonia NOS

The numbers of Pneumonia NOS (no organism specified) were marginally raised this

quarter at 20 (5.73% of diagnosable submissions compared to 4.42% this quarter last

year). There has been a consistent increase in the annual numbers of diagnoses of

pneumonia NOS since 2015. In this quarter most of the diagnoses are in weaned lambs

and are predominantly caused by Bibersteinia trehalosi or may be chronic pneumonia

cases following other bacterial, viral or parasitic infections earlier in the summer.

Figure 25: GB Incidents of Pneumonia – NOS in sheep Q4, as a % of diagnosable submissions 2007-2019

Annual Pneumonia NOS diagnoses have remained relatively high at 90 cases in 2019,

with diagnoses at 3.98% of diagnosable submissions compared to 4.18% in 2018, when

diagnostic numbers are usually between 1.95%-3.52%. There has been a sustained rise

since 2015, and this rise is typically due to more diagnoses of chronic pneumonia in both

adult sheep and post weaned lambs, usually with a history of poor thrift or failure to put on

weight.

19

Annual - Mannheimia sp pneumonia

Pneumonia due to Mannheimia sp cases were relatively high during 2019 (145

diagnoses), consistent with 2018 (195 diagnoses). The Mannheimia pneumonia diagnoses

represented 6.43% of diagnosable submissions in 2019 compared to 6.69% in 2018,

where diagnoses are usually 3.23% to 5.43%. The increase in cases was seen more in

preweaned lambs in 2018, but there were also increased diagnoses in weaned lambs and

adults. During 2019 the increase in cases was seen in preweaned lambs.

Figure 26: Annual GB Incidents of Mannheimia haemolytica in sheep as a % of diagnosable submissions 2007-

2019

Annual - OPA

There was a small increase in the numbers of OPA diagnoses (82 cases were diagnosed

in 2019), the diagnostic rate was at 5.36% of diagnosable submissions, when numbers are

usually 1.44%-4.76%. This rise was influenced by a marked increase in the numbers of

cases diagnosed by SRUC, there were 62 cases diagnosed in 2019 where diagnoses are

usually between 27 and 58 per year. Recently initiated flock scanning to improve

management of the disease and a resultant raised awareness of the disease may have

increased sample submissions to screen for this disease.

Urinary disease, reproductive disease, systemic disease, musculoskeletal disease – No significant trends were identified this Quarter.

Centre of Expertise for Extensively Managed Livestock

During Q4 2019 there were 191 diagnostic submissions for Hill/Upland sheep in GB and

the top ten VIDA diagnoses made for these are shown in Figure 28.

20

Figure 27: Top 10 GB VIDA diagnoses for Hill/Upland sheep Oct – Dec 2019

The most common presenting sign for submissions from Hill sheep was wasting

(Figure 28).

Figure 28: Presenting signs of Hill/Upland sheep from GB submissions Oct – Dec 2019

Cumbria Sheep Scab project update

In the SR Q1 2019 report we provided details of an initiative taken by a group of Cumbria

Fell Farmers who had taken steps to control sheep scab on their area of shared common

grazing. Seven hefted flocks of Herdwick sheep grazed the common and the seven

farmers worked collaboratively to develop an approach to the control of sheep scab on

common grazing.

None of the seven flocks had any obvious signs of sheep scab and all the sheep were

healthy and in good condition. However, some flocks had reported that some sheep were

22

119 9 9

75 5 4 4

59

45

19

12

12

11

10

8

7

4

1

1

1

1

WASTING

FNDDEAD

SKIN

DIARRHOEA & GIT

MALAISE

UNKNOWN

NERVOUS

RESPIR

Others

ABORTION

HEALTHY

MASTCLIN

RECUMBT

REPRO

21

pulling wool in January and some of these sheep did have lice, so the farmers assumed that

lice was the problem. However, sheep scab may also have been present at a very low level

and thus while not showing signs associated with sheep scab, scab mites may have been

present in low numbers and contributing to this wool pulling. If not checked, sheep scab

would continue to circulate even if only at a low level. In addition, scab mites may have been

passed contact at shows or from animals brought in from sales. Evidence of sheep scab was

found in 5 of the 7 flocks on the common using the Sheep scab ELISA test and all flock were

dipped during November in 2018.

The farmers reported in January 2020 that no “itchy sheep” or sheep pulling wool were

observed in the seven flocks in January 2019 nor in January 2020.

The collective and coordinated dipping in the late autumn of 2018 appeared to have

resolved the low level of sheep scab in the flocks and controlled the lice that had been seen

in the sheep in January 2018. Those farmers who had previously dipped their sheep at the

late summer / early autumn weaning gather, delayed dipping until October in 2019 so that all

ewes from the seven flocks were all dipped within the same time frame and returned to the

fell.

This demonstrates that farmers are able to work collaboratively to address sheep scab,

however this requires coordination and support if this approach can be implemented in other

areas.

On 30-31/01/2020 the University of Bristol convened a meeting Sheep scab: identifying

the optimum approach to sustainable management of Industry stakeholders from

across GB and the aim of the meeting is described below:

Psoroptic mange (scab) has a significant effect on the health, welfare and productivity of

sheep in the UK. The incidence of scab has increased year on year since its reintroduction

in 1972 and the recent identification of resistance to one of the two main classes of

licenced treatment means that management will become increasingly difficult in the future.

National eradication is unlikely to be feasible on economic, logistic, or political grounds. As

a result, more coherent approaches to sustainable scab management must be adopted.

Sustainable management means adopting a range of practices that reduce and maintain

the incidence at ‘acceptably’ low levels. However, at present, there is a lack of consensus

about what the optimum approach to future cost-effective sustainable scab management

is. The fact that there is no consensus means that stakeholder groups adopt different

approaches and any message to government is diluted and is therefore unclear.

Implementing management at a devolved government level complicates efforts to control

a trans-national infection. The aim of this meeting is to bring together key opinion leaders

with expertise in different areas related to sheep and scab management to attempt to

identify an underlying consensus on best practice approaches to scab management that

can be promoted to policy makers. The election of a new government, Brexit and a

number of recent technological developments make re-examination of the approaches

used for scab management timely.

22

Horizon scanning

Bluetongue (BTV) update

The risk of introduction of BTV remains low.

For more information, see the updated situation assessment, at:

https://www.gov.uk/government/publications/bluetongue-virus-in-europe

In January 2020, there were reports of BTV-8 in Switzerland (1), Belgium (2), and France

(1), BTV-16 in Greece (1), and BTV-4 in Italy (1). A amp of the current BTV situation in

Europe is shown in Figure 29.

Figure 29: Bluetongue disease in Europe August 2019 – January 2020

AMR related

Veterinary Antibiotic Resistance Sales and Surveillance (UK-VARRS) report published by

the Veterinary Medicines Directorate (VMD) has shown that antibiotic sales for food-

producing animals have fallen by 53 per cent in just four years.

While usage data for sheep is not currently available there is significant work on going

towards developing comprehensive antibiotic usage reporting led by the Sheep Antibiotic

Guardian Group which is a sub group of the Sheep Health and Welfare Group (SHAWG).

23

The VARRS report identified a large increase in resistance to tetracyclines observed in M.

haemolytica from both cattle and sheep in 2017 and 2018, compared to 2016. See also

Disease surveillance in England and Wales, July 2019. Veterinary Record 185, 132-136

https://www.gov.uk/government/publications/veterinary-antimicrobial-resistance-and-sales-

surveillance-2018

Poisoning

The latest Chemical Food Safety report can be found at this link:

https://www.gov.uk/government/publications/chemical-food-safety-reports

Suspected Pieris toxicity in a 7-month-old lamb

A seven-month-old ewe lamb was euthanased for post-mortem examination having been

found recumbent in the field on the morning of submission. Evergreen leaves found in the

rumen were identified as Pieris spp (Figure 30).

Figure 30: Pieris leaves found in rumen

Pieris sp. are very toxic to both animals and humans due to grayanotoxins that bind to

sodium channels of cardiac and skeletal muscle and nerve cells. The toxic dose of fresh

leaves is reported to be 0.1-0.6% of body weight for ruminants, equating to around 30-180

grams of fresh leaves for a 30kg lamb. Advice was given to check field margins for these

plants or for dumping of garden waste. Since the lamb also had a very high worm egg

count indicating a significant gastrointestinal worm burden, worming of the rest of the

group with an appropriate anthelmintic was recommended.

24

Publications

APHA Staff

Giangaspero M; STEINBACH F; STRONG R; Decaro N; Buonavoglia C; Domenis L;

Gargano P; Bailly X; Apicella C; Turno P (2020) Characterization of internal ribosome

entry sites according to secondary structure analysis to classify border disease virus

strains. Journal of Virological Methods 275 113704.

Langeveld JPM; Pirisnu L; Jacobs JG; Mazza M; Lantier I; Simon S; Andreoletti O; Acin C;

Esposito E; Fast C; Groschup M; Goldmann W; SPIROPOULOS J; Sklaviadis T; Lantier F;

Ekateriniadou L; Papasavva-Stylianou P; van Keulen LJM; Acutis P-L; Agrimi U; Bossers

A; Nonno R (2019) Four types of scrapie in goats differentiated from each other and

bovine spongiform encephalopathy by biochemical methods. BMC Veterinary Research

50, Article 97

Other publications of interest

Bangoura B; Bardsley KD (2020) Ruminant Coccidiosis. Veterinary Clinics of North

America: Food Animal Practice 36 (1) 187-203

Ben-Harari, R. R. (2019) Tick transmission of toxoplasmosis. Expert Review of Anti-

infective Therapy 17, 911-917

Burke JM; Miller JE (2020) Sustainable approaches to parasite control in ruminant

livestock. Veterinary Clinics of North America: Food Animal Practice 36 (1) 89-107

Calvete C; González JM; Ferrer LM; Ramos JJ; Lacasta D; Delgado I; Uriarte J (2020)

Assessment of targeted selective treatment criteria to control subclinical

gastrointestinal nematode infections on sheep farms. Veterinary Parasitology 277

109018

Holding M; Dowall SD; Medlock JM; Carter DP; Pullan ST; Lewis J; Hewson R (2020)

Tick-Borne Encephalitis Virus, United Kingdom. Emerging Infectious Diseases, 26 (1),

90-96.

Howell AK; Williams DJL (2020) The epidemiology and control of liver flukes in cattle

and sheep. Veterinary Clinics of North America: Food Animal Practice 36 (1) 109-123

Jahns, H. & Cousens, C. (2019) Nasal adenocarcinoma associated with jaagsiekte

sheep retrovirus infection in a sheep. Journal of Veterinary Diagnostic Investigation,

1040638719897032

Jones, Scott; Eden, Laura; McKay, Heather; Bollard, Nicola; Dunham, Stephen; Davies,

Peers; Tarlinton, Rachael (2019) Schmallenberg virus neutralising antibody

25

responses in sheep. BMC Veterinary Research 15 (1) 426

Lacasta, D., González, J. M., Navarro, T., Saura, F., Acín, C. & Vasileiou, N. G. C. (2019)

Significance of respiratory diseases in the health management of sheep. Small

Ruminant Research 181, 99-102

Mathevon, Y., Foucras, G. & Corbiere, F. (2019) Flock sensitivity and specificity of

pooled fecal qPCR and pooled serum ELISA for screening ovine paratuberculosis.

PLoS One 14, e0226246

Pourmahdi Borujeni M; Haji Hajikolaei MR; Seifi Abad Shapouri MR; Roshani F (2020)

The role of sheep in the epidemiology of Bovine alphaherpesvirus 1 (BoHV-1).

Preventive Veterinary Medicine 174 104818

Redman, E., Queiroz, C., Bartley, D. J., Levy, M., Avramenko, R. W. & Gilleard, J. S.

(2019) Validation of ITS-2 rDNA nemabiome sequencing for ovine gastrointestinal

nematodes and its application to a large scale survey of UK sheep farms. Veterinary

Parasitology 275, 108933

References

PENNY, C., MACRAE, A., HAGEN, R., HAHN, C., SARGISON, N., SCOTT, P., SMITH,

S., WILSON, D. & MAYHEW, J. (2007) Compressive cervical myelopathy in young Texel

and Beltex sheep. J Vet Intern Med 21, 322-327

STURGESS-OSBORNE, C., BURGESS, S., MITCHELL, S. & WALL, R. (2019) Multiple

resistance to macrocyclic lactones in the sheep scab mite Psoroptes ovis. Vet Parasitol

272, 79-82

26

© Crown copyright 2020

Statement regarding use of this material

The material in this report has been compiled by the Animal and Plant Health Agency

(APHA) Surveillance Intelligence Unit in collaboration with the APHA Surveillance and

Laboratory Services Department. Images are governed by Crown Copyright except where

specifically acknowledged to have been provided by others external to APHA. Use of

material directly from the report is acceptable provided APHA (or others where specifically

indicated) is acknowledged as the owner of the material. This does not include use of the

APHA logo which should excluded, or used only after permission has been obtained from

APHA Corporate Communications (apha.corporatecommunications@apha.gov.uk).

You may re-use this information (excluding logos) free of charge in any format or medium,

under the terms of the Open Government Licence v.3. To view this licence visit

www.nationalarchives.gov.uk/doc/open-government-licence/version/3/ or email

PSI@nationalarchives.gov.uk

This publication is available at https://www.gov.uk/government/collections/animal-disease-

surveillance-reports

Any enquiries regarding this publication should be sent to us at SIU@apha.gov.uk

http://apha.defra.gov.uk/vet-gateway/surveillance/index.htm

The Animal and Plant Health Agency (APHA) is an executive agency of the Department for

Environment, Food & Rural Affairs, and also works on behalf of the Scottish Government

and Welsh Government.