1. Introduction
Parasitic diarrheal disease continues to be a major cause of morbidity and mortality in the developing world. Neonatal and young calves are highly susceptible to enteric infections by various pathogens, including bacteria, viruses, fungi, protozoa, and helminths [
1]. The most commonly identified parasitic agents responsible for diarrhea are:
Cryptosporidium spp.,
Eimeria spp.,
Giardia spp.,
Toxocara vitulorum, and
Buxtonella sulcata [
2]. However, bacterial, viral, fungal agents, and nutritional factors also play a role in causing diarrhea [
3,
4]. Diarrhea may occur as a consequence of stress, improper sanitation, or sudden feed changes [
3,
5,
6].
Cryptosporidium is one of the most common enteropathogens present in calves during the first two weeks of age [
7].
Cryptosporidium infection in calves is characterized clinically by non-specific diarrhea, dehydration, depression, anorexia, and abdominal pain. In most calves, diarrhea starts 3–5 days post-infection and lasts from 4 to 17 days [
7,
8].
Bovine coccidiosis is one of the most common parasitic diseases of cattle currently occurring as a subclinical disease, which causes great economic losses [
9]. Coccidial infection affects all age groups but is most common and important in young animals [
10,
11].
T. vitulorum is a nematode living in the small intestine of cattle and water buffalo calves and may also cause diarrhea together with anemia, weight loss, and anorexia in calves aged 1–3 months [
12]. The infection rate is the highest in 1- to 3-month-old calves and decreases as the animal gets older [
13,
14].
B. sulcata is a ciliate with two stages: trophozoite and cyst stages. The trophozoites colonize and invade the colonic wall of cattle and cause diarrhea in calves [
2]. The prevalence rate of diarrhea was substantially higher in calves having
B. sulcata cysts than in those without the cysts [
15]. In several studies,
B. sulcata infection in ruminants is associated with diarrheal symptoms [
2,
16,
17]. However, the association between
B. sulcata infection and other parasitic diseases contributing to diarrhea remains to be investigated. Therefore, in the present study, we tried to investigate the impact of single- and multiple-species parasitic infections on diarrhea in suckling and post-weaning calves. Treatment of buxtonellosis was carried out, and the overall efficacy of oxytetracycline and metronidazole in cattle was 66% and 33%, respectively [
18]. In a previous study, metronidazole, oxytetracycline, and secnidazole were used for the treatment of
Balantidium coli infection in cattle with efficacies of 37.5%, 62.5%, and 87.5%, respectively [
19]. Similarly, oxytetracycline was selected as an antibacterial and antiprotozoal agent for persistent diarrhea in a heifer calf [
20]. Garlic has antiparasitic (antihelminthic) [
21], antiprotozoal [
22], and acaricidal properties [
23]. Garlic activity is based on allicin, which is the main constituent of garlic [
24,
25]. Thus, combinations of antimicrobials with antiprotozoal agents were tested to control buxtonellosis in calves.
4. Discussion
Parasitic diarrhea of calves is a commonly reported disease in young animals. In the current study, fecal examination of 1100 diarrheic calves (cattle and buffaloes) revealed that 224 (20.36%) calves were positive for different intestinal parasites. The prevalence rate of parasitic diarrhea among suckling calves (1–60 d) was 19.83% and 19.14% in cattle and buffaloes, respectively. Moreover, the rate of infection among the post-weaning calves (2–6 m) was 23.22% and 19.19% in cattle and buffaloes, respectively. Similar findings were obtained by Rana et al. [
31] who reported a prevalence rate of infection 16.10% (24/142) in neonatal buffalo calves in Hisar district, Haryana. Our prevalence rates were lower than those previously reported in the literature [
32,
33,
34]. Herein, the most common parasites found in calves were
Eimeria species,
B. sulcata,
Cryptosporidium species, and
T. vitulorum. These results are in agreement with those obtained by El-sherif and Aboelhadid [
35], Reberio et al. [
36], GÖZ et al. [
32], and Ramadan et al. [
34].
In the current investigation,
Eimeria species infection was the most common among suckling calves (37.14% and 40.82% prevalence rates in cattle and buffaloe calves, respectively). These findings are in line with those reported by El-sherif and Aboelhadid [
35] in Egypt (10.50%) and Heidari et al. [
37] in Iran (8.25%). In this respect, Reberio et al. [
36] and GÖZ et al. [
32] reported that the most common parasite in neonatal suckling calves was
Eimeria species. Furthermore, different prevalence rates of
Eimeria species were reported in different regions of the same country (Turkey), for example by Yüksekova-Hakkari (89.13%) [
38] and Yüzüncü Yıl (69.8%) [
39]. These variations could be attributed to seasonal, climatic, and geographical differences and management and husbandry practices of the studied animals in different regions.
The prevalence rate of
B. sulcata ranks second to the most common parasite,
Eimeria species, that causes diarrhea among the examined calves of both ages (32.86% and 30.15%). Some researchers revealed that
B. sulcata can cause diarrhea in cattle and buffalo calves as a result of changes in the parasite microenvironment in the gastrointestinal tract (GIT), especially pH changes [
2,
15]. These results are in line with those of previous studies (Mamatho and Souza [
40] and GÖZ et al. [
32]). However, the rates we determined were lower than those reported by Sultan et al. [
41], Al-Saffar et al. [
42], and Tomczuk et al. [
2] who recorded infection rates of 48.2% in cattle in Egypt and 24.1% in buffalo calves in Mosul province Iraq. These discrepancies in the percentage of infection may be due to the age of the animals, their health status, the number of cysts, and the intensity of infection. In addition, when the diet was changed from freshly cut Berseem (Egyptian clover) to conserved Berseem as silage with an increase in supplementary concentrate feeding, the carbohydrate intake by the animals increased, which might have affected
B. sulcata population dynamics [
42].
Cryptosporidium species were detected in 20.00% and 12.24% of 224 diarrheal cattle and buffalo calves, respectively. This values are lower than those reported by GÖZ et al. [
32], Singh et al. [
22] and Sharma and Busang [
33], who detected
Cryptosporidium spp. in young calves (0–3 months) at prevalence rates of 18.6%, 65.7%, and 30.9 ± 5.6%, respectively. This variation could be attributed to geographical differences, feeding systems, stress, improper sanitation, and technique of examination.
T. vitulorum was a cause of diarrhea in young calves with prevalence rates ranging from 12.24% to 23.80% in cattle and buffalo calves, respectively, for both ages. These findings are in accordance with data published by Riberio, et al. [
36] and Ramadan et al. [
34], who stated that
T. vitulorum was the most helminthic pathogen in diarrheic buffalo calves (17.2%), while its prevalence rate was 12% in cattle calves in Munofyia province, Egypt. This could be partially due to the existence of several routes of transmission, such as trans-placental and trans-mammary transmission or ingestion of larvated eggs. In addition, the data of the present study revealed that
Moneizia species eggs were recorded in post-weaning calves combined with other intestinal parasites, including
T. vitulorum,
Eimeria species, and
B. sulcata, while single-infection diarrheic calves had a mono-infection with
Moneizia species.
At this stage of post-weaning age, the calves begin to eat roughage and green fodders, which may be contaminated with the orbatide mite (intermediate host of anoplocephalids), considered the source of
Moniezia infection [
6]. The study of the association between
B. sulcata and other parasitic infections in this study revealed that the most common pattern of parasitic co-infection was a double infection with
B. sulcata and
Eimeria species and of
B. sulcata with
T. vitulorum. Meanwhile, single infections with
B. sulcata (35 case) were more frequent than
B. sulcata coinfections with other parasites, indicating that
B. sulcata might be the cause of diarrhea. In fact, the number of protozoan pathogens in the feces was high (≤500 cyst per gram), which reflected an increase of
B. sulcata invasion. This could contribute to the acceleration of alimentary content passage in the intestine, resulting in diarrhea [
2,
15]. Moreover, a sudden change in the feeding system affects the digestive tract pH, and an incorrect diet causes diarrhea in calves owing to the multiplication of
B. sulcata and the enhancement of the parasite virulence [
5]. Therefore,
B. sulcata is a frequent cause of diarrhea in calves. However, the association of bacterial, viral, and fungal infections with
B. sulcata remains to be investigated [
43].
The risk factors in this study revealed that the age is one of the major risk factors in the spread of parasitic infections. Furthermore, morbidity and risk of infection are greater in younger animals than in aging animals [
9]. Here, the infection rate was nearly 20%, which may be attributed to the fact that calves are more susceptible to parasitic diarrhea than adults because of their immature immune system [
11,
44,
45,
46]. In addition, calf gender had no significant effect on the infection. However, the findings of the current study do not support previous researches [
36,
42,
47] that recorded higher prevalence rates of intestinal parasites in males than in females. Similarly, Priti et al. [
44], Rehman et al. [
12], and Jahanzaib et al. [
48] recorded a higher prevalence of infections in female cattle and buffalos than in males.
The housing system had no significant effect on the infection rate by diarrheal pathogens. These results differ from other published studies by Ernst et al. [
49], Rehman et al. [
12], and Jahanzaib et al. [
48], which reported that parasitic infections were more common in confined herds than in animals kept on pastures. The current investigation revealed that the feeding system had a great effect on the infection rate by diarrheal parasites (
p < 0.05). For example, dry-mix feed materials were associated with the lowest infection rate among the examined calves. This result may be explained, for suckling calves, by the possible external contamination of udders and the contamination of milk containers and, for newly born calves, by the presence of a less-developed immune system. Similar findings were obtained by Abebe et al. [
10] and Singh et al. [
50], in contrast to earlier findings by Rodríguez-Vivas et al. [
51], Waruiru et al. [
52], Wahid and Soad [
53], Rahmatullah and Kamboh [
54], and Ramadan et al. [
34]. No significant data were obtained in the present study concerning a seasonal effect on the infection rate.
Buxtonellosis in ruminants has not been deservedly studied, and most studies have concentrated on its prevalence. Previous studies have revealed a strong relationship between the intensity of infection (i.e., the number of cysts per gram of feces) and diarrhea in cattle [
2,
55]. Besides, in the current investigation, among the 224 parasitic diarrheic calves, 35 calves had a mono-infection with
B. sulcata and did not respond to antibiotic treatment.
Interestingly,
B. sulcata is not the primary cause of diarrhea, but its infection could be complicated by secondary bacterial infections, which increase the intensity of the clinical symptoms [
2]. This study, therefore, set out to assess the effect of combinations of sulphadimidine with metronidazole or oxytetracycline HCL with metronidazole on buxtonellosis. Remarkably, data showed a complete absence of diarrhea and a significant reduction in the mean fecal cyst count (
p < 0.05) after both chemical treatments.
In addition, animals in group C were administered garlizine as a natural treatment and experienced an improvement in fecal consistency. Furthermore, the cyst count was significantly lower than in the untreated control, though still higher (
p < 0.05) than in the drug-treated groups. This finding is supported by Sivajothi and Sudhakara [
56] who reported that a combination of oxytetracycline hydrochloride, metronidazole, and furazolidone showed a complete elimination of
B. coli cysts or trophozoites by the 3rd day of therapy in buffalo calves. Meanwhile, a previous study by Hasheminasab et al. [
19] recorded that oxytetracycline alone or metronidazole alone showed efficacies of 66% and 33%, respectively, against
B. sulcata. Therefore, the combination of oxytetracylcines, metronidazole, and sulphadimidine are useful therapeutic agents against
B. sulcata infection. Out of 1100 examined calves with diarrhea, 876 calves (79.63%) had no parasites. Furthermore, the combination of oxytetracylcine or sulphadimidine with metronidazole had improved efficacy against
B. sulcata diarrhea. The efficacy of garlizine was lower than that of the above-mentioned drug treatments. Such treatment is safe and has no side effects [
23,
57].