FAQ“s

a) Regarding Isospora suis

Q: Which agent causes piglet coccidiosis?
A: Coccidiosis in piglets is caused by infection with Isospora suis, a protozoic parasite that is very hard to eradicate and is commonly found on swine farms. 

Q: What characterizes the morphology of Isospora suis?
A: The oocysts of Isospora suis (exogenous phase of the life cycle) are spheroid to spherical in shape, measuring 19.4 to 22.5 µ in diameter, with a smooth, single-layer capsule 1.5 µ thick. They contain two sporocysts (disporic) with four sporozoites each (tetrazoic).

Q: Where does Isospora suis spend its life cycle?
A: Isospora suis goes through developmental stages of life both inside the host animal and in the external environment. This parasite targets the small intestine, where it develops in the mucosal tissue. The developmental stages produce a microscopic egg, called an oocyst. The oocysts of I. suis are excreted with faeces. Under proper conditions (temperature, moisture, oxygen), the oocyst will then develop to form a sporulated oocyst within 1 to 3 days. 

Q: What is the duration of the Isospora suis life cycle?
A: In current swine production, where supplemental heat between 32° and 35° C is provided to newborn piglets, oocyst sporulation may occur in 12 to 16 hours. Oocysts are first seen in faeces 5 days post-inoculation.

b) Regarding Piglet Coccidiosis

Epidemiology

Q: Does Isospora suis affect pigs of any age?
A: Isospora suis can infect pigs of any age, but only causes clinical signs in piglets.

Q: Can other Eimeria infect pigs?
A: Yes, but they do not have a detrimental affect on the pigs.

Q: How widespread is the parasite?
A: Reports on the presence, prevalence and epidemiology of Isospora suis have come from Italy, Denmark, France, Portugal, Germany, Malaysia, Australia, North and South America and elsewhere. The studies conducted in these areas show a high prevalence of the disease on farms in most of the reporting countries (45 to 85%), as well as a high incidence of litters affected by the disease (>30%).

Q: How important is the role of the sow in the transmission of the disease?
A: It had been determined that the sow plays a minimal or no role in the transmission of Isospora suis. Lindsay et al. (1984) performed a study in USA, where they examined the oocysts excreted by the sows on farms with and without a history of Isospora suis infections in piglets. The study reported a high infection rate to Eimeria species in the sows but less than 1% with Isospora suis. 

Q: What role does environmental contamination play in the transmission of the disease?
A: The environment is the most important source of infection. Infected piglets excrete more than 100,000 oocysts per gram of faeces, but can become infected with a low dose of Isospora suis (100 oocysts). The oocysts are highly resistant to external influences, and the environment in the farrowing houses is favourable to rapid sporulation and transmission of the disease. Once Isospora is established on a farm, it is most likely transmitted from one contaminated litter to another.

Clinical signs, lesions, and economic significance

Q: What are the main signs of piglet coccidiosis?
A: The main clinical sign of coccidiosis is diarrhoea that varies from white to yellow in colour and from a pasty to a watery consistency. Blood is never present. As a result of Coccidia infection, the incidence of secondary bacterial infections increases, and the daily weight gain of affected animals decreases compared with uninfected animals. Accordingly, weaning herds are highly heterogenous.

Q: Does Isospora suis cause lesions?
A: Isospora suis causes severe lesions in the small intestine, causing large areas of mucous to be destroyed and the intestinal villi to atrophy, becoming shorter.

Q: What economic impact does the disease have?
A: Although the disease has only a slight influence on mortality, it does influence the presence of concomitant infections and the amount of antibiotics needed to control them. Likewise, the disease has a dramatic impact on the development of piglets, causing herds to be uneven at weaning age. In a Danish survey, practitioners noted that the disease reduces growth by 15% on average,  i.e., 500 g at weaning age.

Diagnosis

Q: How can the disease be diagnosed?
A: Diagnosis of neonatal swine coccidiosis due to Isospora suis is based on clinical signs, herd history, and the confirmed presence of the parasite. The endogenous stages in the intestinal epithelium may be identified microscopically in mucosal scrapings. The faeces, however, should be examined for oocysts. The disease must be differentiated from nutritional imbalances and viral or bacterial infections.

Q: When should the faecal sample be taken?
A: Feacal samples should be taken in the second or third week of life. The probability of finding the pathogen in the sample does not necessarily increase by selecting piglets with diarrhoea; diarrhoea can develop before oocysts are excreted in the faeces, and even firm faeces often contain large numbers of oocysts.

Q: How many faecal samples should be taken for Coccidia diagnosis?
A: The sampling of 3 to 5 pigs per litter and at least 10 litters per farm is recommended. Samples from the same littler can be pooled. On large farms, 5 to 10% of litters should be examined.

Q: How should faecal examination be performed?
A: Direct examination of faecal smears for oocysts under an optical microscope is not very conclusive, but certainly can be successful where massive infestation is present. However, it will be necessary to concentrate the samples first. Remember that flotation solutions with higher specific gravity are more suitable for use when flotation is to be carried out.
A saturated NaCl solution with 500 g added glucose per litre can be used as flotation medium. This yields higher numbers of oocysts, which are also more clearly visible.

Q: Are PCR or autofluorescence techniues available for Coccidia diagnosis?
A: Techniques such as PCR or autofluorescence are available for Isospora diagnosis, but they are not as commonly used.

Control

Q: How should the disease be controlled?
A: It is essential to establish programs that combine management, hygiene and chemotherapy to reduce the infection pressure of the parasite and minimize the effects of the disease on animals. It is important to note that anticoccidial therapies serve little purpose once the piglets have started scouring. Therefore, metaphylactic treatment should be introduced during the first week of age to prevent the damage to the piglets caused by Isospora suis.

Q: Can a powerful disinfecting program prevent the disease?
A: Coccidia oocysts are resistant to many disinfectants, although procedures such as cleaning pens properly with high-pressure hot water (>70° C) and keeping them dry during the first weeks of farrowing will help reduce the number of oocysts. Disinfection in farrowing houses is essential to reducing infection pressure on newborn piglets, but it is not enough to control the problem entirely.  

Q: What about immunity to the disease?
A: Infected neonatal piglets display a high degree of acquired immunity to subsequent reinfection with Isospora suis. This immunity, however, develops too slowly to offer meaningful protection against the initial clinical disease.

Q: What experience has there been with chemotherapy?
A: Anticoccidial therapy serves little purpose once the piglets have started scouring. Several attempts to use chemoprophylaxis have been tried with different compounds, but most of these regimes yielded disappointing results and were found to be too labour-intensive for practical use. Even in piggeries affected by coccidiosis, a single oral treatment with 20 mg of Baycox® 5% (toltrazuril) per kg live weight given to all piglets aged 3 to 5 days has been found to deliver excellent results. 
 

c) Regarding Baycox® 5%

Q: What does  Baycox® 5% contain?
A: Each ml of Baycox® 5%  contains 50 mg of toltrazuril.

Q: What is the mode of action of Baycox® 5%?
A: Baycox is active against all intracellular developmental stages of Coccidia, including schizonts, micro- and macrogamonts. It interferes with the division of the protozoal nucleus, the activity of the mitochondria, and damages the wall-forming bodies in the microgametes. Baycox produces severe vacuolisation of the protozoal endoplasmic reticulum in all intracellular developmental stages.

Q: How should Baycox® 5% be administered to piglets?
A: Oral administration of a single dose (20 mg per kg live weight) at 3 to 5 days of age.

Q: What is the recommended dose of Baycox® 5% for piglets?
A: The recommended dose of Baycox® 5% is 20 mg per kg of live weight, or 1 ml Baycox® 5% per 2.5 kg.

Q: What are the main benefits of using Baycox® 5%?
A: A decrease in the incidence of clinical diarrhoea, better weight at weaning age, a decrease in the use of antibiotics for concomitant bacterial infections in piglets following Coccidia infections, more uniform weaning batches with fewer weak piglets (characteristic of problem herds), and satisfaction on the part of vet and farmer at finding a solution to early diarrhoea problems.