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Episode with a high mortality in the weaning stage

The nervous system symptomatology is characterized by some cases of meningitis and opistothonus, dizziness and serious deep depression in a great number of animals. The necropsy shows, in all the cases, a serious lung congestion and an enteritis with a variable seriousness with a more or less important involvement of the mesenteric lymph nodes.

Monday 15 October 2012 (6 years 2 months 4 days ago)
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Description of the farm

It is a site 2 in which we enter 21 day old piglets that come from a site 1 located some 500 km away. The site 2 is filled up with 2 batches of 1,000 weaned piglets with a seven day interval. This clinical case happened on June 21st and 28th 2012. The sanitary state of the site 1 is as follows: PRRS +, Mycoplasma Hyopneumoniae +, Circovirus +, App +, Hps +, Steptococcus Suis Type 2 +, Aujeszky -, Mange -. In the site 2 there in an all-in-all-out management.

The farm in question pertains to an integrated production system that has a great amount of anamnestic data relative to the pigs and their origin. The data tell that the pathogen that normally manifests is Strepococcus Suis Type 2. The strategic medication that is regularly carried out bears especially in mind this fact and the risk, always present, of an enteritis due to E. Coli. The piglets arrive regularly vaccinated against PCV2 and Mycoplasma hyopneumoniae. The farm is PRRS-positive.

The feeding scheme and the medication used is as follows:

1st week (1.5 kg/pig): Prestarter + 3,000 ppm ZnO and Amoxicillin in the drinking water
2nd-3rd week (6 kg/pig): Link feed + 600 ppm Amoxicillin and 180 ppm Colistin
4th-6th week: Starter + 3,000 ppm ZnO
7th-9th week: Starter without medication

CalendarAppearance of the case and first actions (days 0-7)

On July 3rd and 4th some piglets appeared with nervous system symptomatology. Knowing the origin of the animals, an injectable therapy with amoxicillin administered to the affected piglets was adopted.

During the visit carried out on July 6th, as necropsy was performed on two piglets: a slight enteritis was seen with an affection of the lymph nodes. Some animals were sent to the laboratory for a more precise diagnosis and, meanwhile, we used gentamicin in the drinking water.

During Sunday the 8th and Monday the 9th of July, the number of animals with a nervous system symptomatology increased a 20%: we proceeded to carry out a therapy with amoxicillin in the drinking water and we injected amoxicillin to all the pigs (2,000 animals, approximately). At that time, the number of dead piglets was 26 out of the 2,026 piglets that entered the farm (1.28%). As it can be seen in the calendar, on July 5th 14 piglets died, whilst between Sunday the 8th and Monday the 9th of July 12 more animals died. The nervous system symptomatology is characterized by some meningitis, opistothonus, dizziness and deep depression cases in a great number of animals.

The necropsy showed, in all the cases, a serious lung congestion and an enteritis with a variable seriousness with a more or less important affectation of the mesenteric lymph nodes.

Severe lung congestion and an enteritis with a variable seriousness with a more or less important involvement of the mesenteric lymph nodes.

Diagnoses and measures taken (day 8)

On June 10th in the morning, the symptomatology did not show signs of improvement, and there were even new pigs with the same symptoms. Lastly, the diagnosis laboratory informed, via the telephone, that haemolytic E. coli was isolated and that it had an antibiogram that offered very few solutions.

Sample 1 INTESTINE Identification
Parameter/method Result Unit of measurement Uncertainty Limit Start End
Gastrointestinal pathogens Haemolytic Escherichia coli       Jul 6th Jul 7th
Microbiological: MI MD 12 rev. 0 of Dec 9th 2004            
             
Antibiogram See appendix       Jul 9th Jul 11th
Kirby-Bauer: MI MD 08 rev. 0 of Nov 26th 2004            
             
Sample 2 INTESTINE Identification
Parameter/method Result Unit of measurement Uncertainty Limit Start End
Gastrointestinal pathogens Haemolytic Escherichia coli       Jul 6th Jul 11th

Microbiological: MI MD 12 rev. 0 of Dec 9th 2004

           
             
Sample 3 HEAD Identification
Parameter/method Result Unit of measurement Uncertainty Limit Start End
Streptococcus suis Negative       Jul 6th Jul 11th
Microbiological: MI MD 06 rev. 0 of Nov 15th 2004            
             
Sample 4 HEAD Identification
Parameter/method Result Unit of measurement Uncertainty Limit Start End
Streptococcus suis Negative       Jul 6th Jul 11th
Microbiological: MI MD 06 rev. 0 of Nov 15th 2004            

ATTACHED ANTIBIOGRAM

Material: swine intestine

Sample nº 1 Ident. Microorganism Antibiotic Result
    Escherichia coli

Enrofloxacin
Marbofloxacin 2
Amoxicillin + clavulanic acid
Penicillin
Trimethoprim + sulfamethoxazole
Aminosidin
Amoxicillin
Apramycin
Colistin
Flumequine
Gentamicin
Tulathromycin

I
I
R
R
R
R
R
R
R
R
R
I

Key: R = Resistant; I = Intermediate; S = Sensitive

After the laboratory report we injected all the piglets with Enrofloxacin with a new formulation that guarantees a 48 hour coverage plus a rehydrating solution in the case of the more severely affected pigs. On that same day, we sent several animals more to another laboratory more specialized than the first one.

At the same time, given the limited information of the antibiogram, we decided to administer a product based in the oxolinic acid in the drinking water that, according to the experience of the veterinarian had given good results in similar cases. At the same time, we also gave a compound feed with a high fibre content and medicated with 3,000 ppm of ZnO.

Evolution of the case, new measures (days 9 - 14)

During the two following days the mortality went on in the already affected pigs and some new cases appeared. The total losses already exceeded a 10% and the majority of the animals ate very little food and the water consumption was scarce. It was decided to withdraw the medication and we administered a rehydrating/detoxifying product in the drinking water based on mineral salts, sugars, amino acids and vitamins in order to "feed" the animals and, especially, to reinstate the virtuous circle > water consumption > feed consumption > water consumption.

The water consumption returned to normal, the compound feed consumption started to increase and on Monday July 16th a group of animals started to show signs of returning to normality: mortality, nevertheless, reached more than a 15%. The pigs that were affected and severely weakened almost always died within 48-72 hours. Samples and entrails of the animals were taken and they were sent to the diagnosis laboratory.

Confirmation of the laboratory results

The laboratory results in relation to the sending of samples on June 10th shows, as in the first case, enteritis, lymphadenitis and lung congestion. Streptococcus suis was isolated from the brain of a pig and from the endocardium of another one.

Material sent: LIVE ANIMAL/CARCASS Species: SWINE
Reason of the sending: Diagnosis
Number of samples: 5
Conditions of the supplied material: Suitable

RESULTS OF THE TESTS

1st Test: Anatomopathological examination of medium/small-sized animals
Technique: Anatomopathological
Test Method: NK 2629
Samples: 1-5
Results: Lung congestion. Hyperplasia and congestion of the mesenteric lymph nodes in the case of sample no. 1.
Lung congestion. Follicular hyperplasia of the colon. Hyperplasia of the mesenteric lymph nodes. Congestion of the meningeal and brain vessels in the case of sample no. 2.
Lung oedema. Hyperplasia of the mesenteric lymph nodes in the case of sample no. 3.
Lung oedema. Congestion of the brain and the meningeal vessels in the case of sample no. 4.
Fibrinous perihepatitis. Fibrinous periepicarditis, ulcerous-polypoid endocarditis in the case of sample no. 5

2nd Test: Bacteriological exam
Technique: Microbiological
Test Method: MP 01/181 rev. 0
On the samples: 1-5
Result: Negative for pathogens in the case of samples no. 1, 2 and 3
Streptococcus suis in the brain of sample no. 4
Streptococcus suis in the endocardium of sample no. 5

3rd Test: PRRS: etiologic agent
Technique: PCR
Test Method: NK 1651
On the samples: from no. 1 to no. 5 (in a pool)
Detail: Pool No. 1
Result: No presence is shown

4th Test: Aujeszky's disease: etiologic agent
Technique: PCR
Test Method: NK 2086
On the samples: 2
Result: No presence is shown

5th Test: Encephalomyocarditis cardiovirus: etiologic agent
Technique: PCR
Test Method: MP 09/051 rev. 0
On the samples: from no. 1 to no. 5 (in a pool)
Detail: Pool Nr.1
Result: No presence is shown

6th Test: Antibiogram
Technique: Kirby-Bauer
Test Method: NK 122
Etiologic Agent: Streptococcus suis
Samples: 5
Sensitive to: Amoxicillin, Amoxicillin + Clavulanic Acid, Ampicillin, Cefquinome, Ceftiofur, Tiamulin, Tylosin
Resistant to: Cefalexin, Lincomycin, Penicillin, Tetracycline, Trimethoprim + Sulfonamides

7th Test: Bacteriological exam
Technique: Microbiological
Test Method: MP 01/103 rev. 1
Samples: 2
Absence

The acronyms MP or NK identify an `Internal test method`.

*** END OF THE REPORT ***

On the following days, from the results related with the samples sent to the laboratory on July 16th, emerges the presence of of several E. Coli strains, haemolytic or not. The genotypification of these strains shows the presence of the genes Stb and LT (although diarrhoea has never been a predominant symptom), and specially the genes VT2.

Material sent: LIVE ANIMAL/CARCASS/ pigs of approximately 40 days old
Species: SWINE - WEANING
Reason of the sending: Diagnosis
Number of samples: 5
Sampling date: July 16th 2012
Conditions of the supplied material: Suitable

RESULTS OF THE TESTS

1st Test: Anatomopathological exam of big sized animals
Technique: Anatomopatological
Test Method: NK 2627
On the samples: 1-5
Results: enteritis, lymphadenitis and lung congestion in the case of the samples no. 1, 2, 3, 4 and 5

2nd Test: Bacteriological exam
Technique: Microbiological
Test Method: MP 01/181 rev. 0
On the sample: 1
Result: Non- haemolytic E.coli (K88 NEGATIVE) in the case of the samples no. 1, 2, 3 and 4.
Presence of haemolytic E.coli in sample no. 5 (K88 NEGATIVE).
The presence of Salmonella is not proven in any of the samples.
Presence of Streptococcus in the brain of sample no. 4. The rest of the samples are negative for sample no. 1.

3rd Test: Genotypification of enterotoxigenic E.coli (ETEC)
Technique: PCR Multiplex
Test Method: NK 2405
On the sample: 5
Result: The presence is not shown in the case of the analysed sample.

4th Test: Genotypification of enterotoxigenic E.coli (ETEC)
Technique: PCR Multiplex
Test Method: NK 2405
On the samples: from no. 1 to no. 4 (in a pool)
Detail: Pool no. 1
Result: The presence of the genes Stb and LT is shown.

5th Test: Verotoxins codifying gene/genes (VTEC) Escherichia coli
Technique: PCR Real Time
Test Method: MP 09/109 rev. 1
On the sample: 1
Result: Presence of the gene VT2 in the analysed sample

6th Test: Antibiogram
Technique: Kirby-Bauer
Test Method: MP 01/068 rev. 0
Etiologic Agent: Escherichia coli
Sample no.: 1
Sensitive to: Aminosidin, Cephalexin, Ceftiofur, Colistin, Neomycin
Resistant to: Amoxicillin, Amoxicillin + Clavulanic Acid, Apramicin, Danofloxacin, Enrofloxacin, Florfenicol, Flumequine, Gentamycin, Marbofloxacin, Penicillin, Espectinomycin, Tilmicosin, Trimethoprim + Sulfonamides

7th Test: Antibiogram
Technique: Kirby-Bauer
Test Method: MP 01/068 rev. 0
Etiologic agent: Haemolytic Escherichia coli
Sample no.: 5
Sensitive: Apramycin, Ceftiofur, Flumequine, Gentamycin
Resistant to: Aminosidin, Amoxicillin, Amoxicillin + Clavulanic Acid, Cephalexin, Colistin, Danofloxacin, Enrofloxacin, Florfenicol, Marbofloxacin, Neomycin, Penicillin, Espectinomycin, Tetracycline, Tilmicosin, Trimethoprim + Sulfonamides

8th Test: Antibiogram
Technique: Kirby-Bauer
Test Method: MP 01/068 rev. 0
Etiologic agent: Gen. Streptococcus
Sample no.: 4
Sensitive to: Amoxicillin, Amoxicillin + Clavulanic Acid, Ceftiofur
Intermediate to: Trimethoprim + Sulfonamides
Resistant to: Ampicillin, Cephalexin, Danofloxacin, Enrofloxacin, Erithromycin, Lincomycin, Marbofloxacin, Penicillin, Spiramycin, Sulfadiazine, Tethracycline, Tylosin

SPECIFICATIONS OF THE TEST

Test: Genotypification technique of enterotoxigenic E.coli (ETEC): PCR Multiplex Sample Method: Not codified
The method implies the detection of genes that codify for K99, K88, 987P, F41, F18, Sta, Stb and LT.

Test: Escherichia coli verotoxin codifying genes (VTEC) Technique: PCR RealTime Test method: MP 09/109 rev. 1
The method detects the presence of genes VT1, VT2 and eae.

CONSIDER AS NEGATIVE for VTEC only if the result is one of the following cases:
- absence
- presence of only the VT1 gene
- presence of only the gene eae

The acronyms MP or NK identify an `Internal test method`.

*** END OF THE REPORT ***

Solution and conclusions

The mortality rate starts to diminish significantly, but the number of piglets that cannot get back to a productive life is very high: On July 19th euthanasia was performed on these animals. On July 27th the total number of dead pigs was 442 with respect to the 2,025 that entered the farm (21.83%).

Mortality

From the moment in which the piglets are part of an integrated production system, the main concern was the one relative to the groups of piglets weaned later from the same site 1: for the moment nothing abnormal is seen.

So, we follow on with the eternal question that does not find a convincing answer: Where did an E. Coli as a pathogen come from?; and the next challenge will be to evaluate what is going to happen with the same pigs from the same source in the same site 2.

Without a doubt, we have seen what a severe enterotoxaemia due to E. Coli could cause: severely depressed animals that could not get up to eat nor drink. Under this situation, the antibiotic administered in the water or the food does not arrive to its destination. The rehydration helped the animals to stand up, probably due to the sugared water, that encouraged them to drink. If they start to drink and eat, then the antibiotic achieves its effect.

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Article Comments

This area is not intended to be a place to consult authors about their articles, but rather a place for open discussion among pig333.com users.
18-Mar-201326431669452643166945when I first see the kinescope ,i was shock.so many dying pigs and dead swine.i did not guess its origin was strap.the contral measure is effective .but i didnot understand the diagnosis list ,can you make a explain the table and list for me ?thank you !
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