Coccidiosis and iron deficiency anaemia CAN WE DO BETTER?
DR. DANIEL SPERLING, DR. NICOLAS GUERRA AND DR. HAMADI KAREMBE
○ Introduction Coccidiosis, which manifests with symptoms of diar- rhoea of varying severity, is probably one of the most frequent and adaptable parasitic infections affecting piglets before weaning. This disease is caused by the small parasite Cystoisospora suis (formerly known as Isos- pora suis), which multiplies inside host cells in the small intestine. Each ingested sporulated oocyst (the external stage of the parasite) from a contaminated environment has the potential to destroy thousands or even millions of intestinal tract epithelial cells. The negative impact is significantly increased in the case of infection and colo- nisation by other intestinal pathogens, especially Clostridium perfringens type A or rotaviruses. This infec- tion leads to damage of the small intestine and, conse- quently, causes diarrhoea and poor performance which affects the final growth of piglets. The negative impact of coccidiosis can clearly be seen even in cases of sub- clinically infected farms which do not present cases of diarrhoea (Maes et al., 2007). Iron deficiency anaemia (IDA), which requires supplementation, is the most com- mon deficiency during the early postnatal period in pigs. The main reason for IDA is that piglets are often born anaemic, with extremely limited iron stores present in the body (Sperling et al., 2018). Without effective external
Figure 1 - Correlation between shedding during infection, quantified as the number of oocysts per gram of faces (OpG) and the faecal score (FS) from a large-scale analysis. Of note, shedding usually starts before the onset of diarrhoea (Joachim et al., 2018b). 50,000
45,000 40,000 35,000 30,000
25,000 20,000 15,000 10,000 5,000 0
4 5 6 7 8
days post infection 11 12 13 14 15 16 17
9 10 FS OpG
supplementation with optimised forms of iron, piglets can develop IDA as early as the second week of life. IDA is characterised by small red blood cells that contain lower haemoglobin (Hb) concentration than normal (called ‘mi- crocytic hypochromic anaemia’) and is frequently report- ed at weaning, even in countries with well-established swine production. The first sign of clinical IDA is a rough- ness of the hair coat and loss of mucus membrane pig- mentation (typical pallor). The skin often becomes wrin- kled, and the pigs become listless with drooping heads and ears, have a lack of appetite and show reduced weight gain (Svoboda & Drabek, 2005). The negative im- pact of anaemia on production results can clearly be seen in the following period; as described in the litera- ture, piglets that were anaemic at weaning were 0.82 kg lighter three weeks later than piglets that had normal Hb values at weaning (Perri et al., 2016).
4.00 3.50
3.00 2.50 2.00 1.50 1.00
○ Diagnosing coccidiosis and iron deficiency anaemia It may be necessary to detect C. suis infections in pigs in a variety of contexts, and techniques are available to do so. The life cycle stages of C. suis can be found in histo- logical sections and impression smears in post-mortem examinations of dead piglets, and these can be helpful in cases of prepatent infections and to determine the ex- tent of the pathological changes caused by the infection (Joachim & Schwarz, 2015). However, mostly from the practical point of view, post-mortem assessments are not widely used. In addition, because other enteropathogens may be in- volved, tests are routinely performed to detect oocysts in faeces and thereby diagnose the presence of an infec- tion in a litter or a herd, usually in relation to clinical signs such as diarrhoea and poor growth performance (in the case of C. suis). The status of animals as shedders can also be determined to estimate the extent of envi- ronmental contamination by clinically healthy carriers. In some cases, usually in experimental studies (Joachim et al., 2018a), the efficacy of control strategies is evaluated by determining oocyst excretion after intervention.
○ Several points need to be considered for proper diagnosis in piglets (Joachim et al., 2018b) • To accurately determine infection, a litter or a herd should be targeted.
2
Mean oocysts per gram of faeces (OpG)
Mean Faecal Score (FS)
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