Trichuris, a genus of whipworms in the family Trichuridae, belongs to the order Aphasmidea, Trichuridae, trichuris, and is a parasitic nematode commonly found in the intestines of humans and animals.[1] Porcine coccidiosis is a protozoal disease with diarrhea as the main clinical symptom caused by Isospara suis and certain Eimeria coccidiosis parasitizing intestinal epithelial cells in lactating and newly weaned piglets. E. coli is a conditional pathogenic bacteria that inhabit the intestine and constitute an important part of the intestinal flora; under normal conditions, it is not pathogenic, and when the body's immunity declines, E. coli invades the intestinal tissue and causes the body to become ill. The E. coli that causes diarrhea in newborn piglets is mainly enterotoxin-producing E. coli (ETEC), whose pathogenicity is related to its adhesin and enterotoxin virulence genes[2].
At present, with the continuous improvement of pig farm hardware facilities, the conditions of the barn are getting better and better, the deworming procedure is more reasonable, and most farms pay attention to the control and treatment of viruses and bacteria when dealing with diarrhea, and often ignore the influence of parasites. However, in recent years, the phenomenon of uncontrollable diarrhea caused by whipworms in pigs has been occasionally reported, resulting in huge losses in pig farms. In order to reduce the occurrence of misdiagnosis in the clinical treatment of diarrhea in pigs, a case of pig whipworm mixed coccidiosis and E. coli infection is reported.
<h1 class="pgc-h-arrow-right" >1 onset of the disease</h1>
In August 2018, a fattening farm with more than 5,000 sows in a 2,000-head pig farm in Guangdong had a serious diarrhea phenomenon; the incidence of diarrhea was high, and the peak mortality rate was about 20%; the pig farm used various antibiotics to treat, which was difficult to cure, and the disease had lasted for more than 1 month.
The survey shows that in June 2018, the fattening pigs in this farm occasionally had a thinning phenomenon (more than 80Kg), the effect of antibiotic treatment was good and bad, and the resulting losses were also within the controllable range; by August 2018, the fattening pig herd had used antibiotics such as doxycycline, florfenicol, amoxicillin, tysecond and quinolones for treatment, and antibiotic treatment had a certain effect, but it was not effectively controlled; finally, in addition to the small proportion of pig diarrhea in the pig population within 15 days of the nursery pig transfer to the farm, Other pigs have seen deaths due to severe diarrhoea.
Recently, viral diarrhea was ruled out by laboratory tests, coccidiosis and E. coli were detected, and susceptibility tests were done on E. coli (see Figure 1-2); finally the feed colistin sulfate treatment was selected, but the effect was not satisfactory, or repeated diarrhea. All the fattening pigs in the farm are transferred to the farm after the conservation and deworming, and the newly transferred pigs also have diarrhea, so the possible pathogen that the pig farm veterinarian first ruled out was intestinal parasites.
Figure 1 CSFV detection and bacterial isolation and susceptibility test
Figure 2 Parasite test results
<h1 class="pgc-h-arrow-right" >2 clinical symptoms</h1>
Different day-old commercial pigs have diarrhea, and the diarrhea manifests itself differently: the stool is watery, mushy, and partially bloody or mucus. The body temperature of the affected pigs is normal, the skin is pale; although most of the appetite is normal, there is a partial decrease in feeding intake; the diarrhea pigs are gradually dehydrated, the same pig is recurrent, and the emaciated exhaustion dies (see Figure 3-4). The incidence of diarrhea is about 60%, and the mortality rate is 10-20%, especially in the 30-60 days after the transfer of conservation to fattening.
Figure 3, Figure 4
< h1 class="pgc-h-arrow-right" >3 autopsy changes</h1>
The results of the autopsy of pigs showed that there were no obvious pathological lesions in the heart and lungs, the liver was black and swollen, the kidneys were bruised, and there were gray-white nodule protrusions on the surface of the colon; the dissection of the colon found catarrhal inflammation of the colon mucosa, mucosal edema, hyperemia, bleeding, and some serious entire colonic edema and congestion; part of the colon scraped off the intestinal contents and inflammatory secretions, and there were a large number of milky white insect bodies, and the worm body was 20-50 mm long (see Figure 5-10).
Figure 5, Figure 6
Figure 7, Figure 8
Figure 9, Figure 10
<h1 class="pgc-h-arrow-right" >4 differential diagnosis</h1>
At present, nematodes are mostly identified by traditional morphological methods. Identification of whipworm insect body: the insect body is whip-shaped, milky white; the anterior part is slender filamentous, accounting for about 2/3 of the length of the entire insect body, and there is a string of single cells around the outside; the posterior part is the body part, which is relatively chaotic, short and thick, accounting for about 1/3 of the length of the entire insect body, and there are intestinal tubes and reproductive organs inside; the female worm length is 39-53 mm, the rear end of the insect body is blunt and round, and the thick junction is the pudendal gate; the male worm length is 20-55 mm, the rear end of the worm body is curled, the tail end has a confluent cavity, and there is a cross-thorn. At the same time, laboratory-confirmed samples were present with spore coccidioides such as pigs and E. coli infections. Taken together, this fattening herd is typical of whipworm mixed coccidiosis infection, with secondary infection with E. coli. (See Figure 11)
Figure 11
< h1 class= "pgc-h-arrow-right" >5 control measures</h1>
(1) Whole-group deworming, feed with ivermectin and fenbendazole powder; "through the extinction" of partial feeding reduction or intramuscular injection of pigs that do not eat; strengthen deworming once after one month.
(2) After deworming, add 2 kg of Ligao 44 and sulfa hexamethyl sulfonamide per ton of feed to control pathogenic E. coli and coccidiosis.
(3) Strengthen biosecurity measures; try to achieve full in and all out, and use Yum-30 to disinfect the environment regularly.
(4) Breeding farm piglets to strengthen the early control of coccidiosis, piglets weaning to nursery each head injection "through" 0.3 to 0.4 ml, transferred to the fattening farm must be dewormed in time as planned.
After the above measures, the condition was effectively controlled within 1 month.
<h1 class="pgc-h-arrow-right" >6 Summary and discussion</h1>
This is a case of trichomycete mixed isochlor, with secondary escherichia coli infection and diarrhea. Since the pig farm does have pathogenic E. coli infections that cause diarrhea in the newly transferred pigs, and the pigs are transferred to the farm after deworming, the veterinarian of the pig farm ignores the problem of parasitic infection, so that the disease of the pigs is delayed and the loss is aggravated.
(1) Most of the infection of pig whipworm is limited to the ileocecal intestine, and the head of the adult worm has a long esophagus so that the head body burrows into the intestinal mucosa, so it is called hairy whipworm; the eggs are brownish yellow, waist drum-shaped, the egg shell is thick, there are egg caps at both ends, and the size is 52-61 μm× 27-30 μm. Adults lay eggs in the cecum, which can lay 5,000 eggs per day, and after excretion with feces, develop into infective eggs at 33-34 °C after 19-22 days [3]. After the infected eggs enter the digestive tract, the first stage of larvae hatches in the posterior segment of the small intestine, migrates to the cecum after 8 days, and develops into adults 30-40 days after infection. The incidence and death of this farm are mainly concentrated in the pig herd after turning over one month, so it indicates that there are a large number of infected eggs in the field environment.
The results of the first test led to a misdirection of the farm's subsequent treatment. The reason is that the disease material of the pigs sent for examination comes from pigs that have just become ill at a smaller age, which may be in the early stage of infection, so no adult worms have been seen; it may also be a problem at the sampling site, and no insect bodies have been found; in addition, due to the small size of whipworm eggs, the laboratory is prone to missed tests.
(2) All the disease materials detected in the two tests of pigs and other spore coccidioides (I.suis), I. suis is the main pathogenic factor of lactating piglets, causing piglets to lose appetite, severe diarrhea, wasting and even death; adult pigs are not easy to be infected or asymptomatic after infection. I. suis infection will induce piglets to be secondarily infected with intestinal bacteria, causing enterotoxic syndrome necrotizing enteritis, increasing the ratio of feed to meat, morbidity and mortality. Therefore, the pig herd that has just been transferred from conservation, coupled with stress and other factors, secondary infection with E. coli causes thinning, but the proportion is low, most of them are in the turn half a month after the onset of the disease began to increase, indicating that it is likely to be infected with pig whipworm at this time.
(3) In general, the products excreted or secreted by intestinal parasites in the host intestine will cause changes in the intestinal environment, resulting in intestinal microbial flora disorders, which is easy to cause the occurrence of intestinal bacterial diseases. In addition, the head of the pig whip worm burrows into the mucosa of the digestive tract to suck blood for a living, resulting in mechanical damage to the mucous membrane and easy secondary bacterial infection.
Clinically, we also need to pay attention to the difference with ileitis, Clostridium enteritis, swine dysentery, Salmonella and viral diarrhea. Make good use of laboratory testing tools to make timely and accurate diagnoses and reduce losses. Finally, farm hygiene and biosecurity are also very important, and eggs released by whipworms and other parasites have long-term vitality in the environment (especially in the soil), so pig farms need to use efficient deworming drugs on a regular basis according to the plan.
< h1 class="pgc-h-arrow-right" >7 Reference</h1>
Kong Fanyao. Livestock parasitology[M]. Beijing:Agriculture Press,1983,247.]
[2] Klobasa F, Butler J E. Absolute and relative concen-trations of immunoglobulins G, M, and A, and alburainin the lacteal secretion of SOWS of different lactation numbers [J]. American Journal of VeterinaryResearch,1987,48(2):176—182.
[3] Burden DJ, Hammet NC, A comparison of the infectivity of Trichuris suis ova embryonated by four different methods [J]. Vet Parasitol,1976,2(3):307-311.