Microscopic examination of internal parasites in Iraqi camels (Camelus dromedarius) with molecular focus on Trichostrongylus spp.

One humped camel species, the camel (Camelus dromedarius), is a significant livestock species that is ideally suited to hot, arid environments (Guliye et al., 2007). Camels were infected by a large number of parasites, many of which are the cause of enteric infection (Wahba & El-Refaii, 2003; Parsani et al., 2008). In the gastro-intestinal tract of camelids, helminthic infections can be either frequent or infrequent. Some helminthes are only found in camelids, but others are also found in other hosts, particularly domestic ruminants and wild animals (Wernery & Kaaden, 2002). The significance of parasites in camel husbandry may be much more significant because they have an impact on camel productivity and performance, as well as their susceptibility to other infectious diseases. Knowledge on controlling parasitic diseases and managing camel husbandry is still very unreliable and insufficient (Borji et al., 2010). Considering the economic importance of camels’ participation in the production of meat in Iran’s Mashhad slaughterhouse, extensive research on gastrointestinal parasites in camels is required (Borji et al., 2010). Common camel parasite infections result in significant economic losses due to reduced working capacity, growth, and productivity (Parsani et al., 2008). The ability of camels, among other domestic animals, to survive a range of economically relevant parasitic illnesses is noteworthy (Soulsby, 1968), and those infected with internal parasites are known to significantly reduce production, usually in severe cases (Abubakr et al., 2000). For those who work closely with camels, some gastrointestinal parasites also have zoonotic significance (Tajik et al., 2011; Lone et al., 2012).

The purpose of this research is to shed light on the main parasites that affect camels. Considering their importance to livestock and the paucity of previous studies on the topic, we have decided to look into this area.

Ethical regulations and procedures are strictly evaluated in the treatment of animals used in scientific research, with special attention to the health of camels. The regulatory agency and the Institutional Review Board (IRB) approved the collection of stool samples from Governorates (Al-Diwaniya and Al-Najaf). This ensures that all procedures comply with international animal welfare regulations and standards. The study used a variety of tools to handle, collect samples and monitor camels to reduce pain and stress in the camels. In addition, permission was obtained from the authorities or guardians to check the health of the camels in the designated area.

In the study, a total of 200 parasite samples were analyzed across four categories. The majority of samples belonged to the Nematodes category, with 112 samples, accounting for 56 % of the total. Protozoa constituted the second largest category, with 57 samples, representing 28.5 %. Cestodes comprised 29 samples, making up 14.5 % of the total. Trematodes were the least prevalent, with only 2 samples, accounting for 1 %. Overall, the combined total of all categories equaled 200 samples, representing 100 % of the analyzed population. (Table 1)

Various parasites were examined across different categories. Among the Nematoda, Trichostrongylus spp. was the most prevalent, with 66 samples accounting for 33 % of the total. Strongyloides spp. followed with 16 samples (8 %), while Nematodirus spp. had 12 samples (6 %). Haemonchus spp., Dictyocaulus spp., and Trichuris trichura were also identified, with 7(3.5 %), 6 (3 %), and 5 (2.5 %) samples, respectively. In the Cestoda category, Fasciola hepatica was the most prevalent, with 21 samples representing 10.5 % of the total. Anoplcephala perfoliata and magna followed with 8 samples (4 %). In the Trematoda category, Paramphistomum cervi was found in 2 samples, accounting for 1 %. Among the Protozoa, Moneizia benedeni was the most prevalent with 25 samples (12.5 %), followed by Giardia spp with 14 samples (7 %),

Eimeria spp. with 12 samples (6 %), Entamoeba spp. with 4 samples (2 %), and Balantidium coli with 2 samples (1 %). The total number of samples analyzed was 200, representing 100 % of the studied population. In summary, nematode infections predominated, with Trichostrongylus spp. being the most prevalent specific parasite genus. Multiple parasite genera were common as mixed infections in the camels. (Table 2)

Microscopic and molecular examination of Trichostrongylus spp.

The prevalence of infected camels with Trichostrongylus spp. depends on the microscopic examination

After the microscopic examination as shown in Figures 1B, 4A, 5B, and C, Trichostrongylus comprised the highest proportion of parasites, accounting for 33 % (66 out of 200). The egg of the Trichostrongylus characterized by small, oval-shaped eggs with a smooth outer shell. Besides Trichostrongylus spp., these figures also depicted the presence of various other parasites, as detailed below: (A) Trophozoite of Entamoeba spp.: A single-celled organism with an irregular shape and movement, varying in size and appearance. (B) Cyst of Giardia spp.: A small, oval or pear-shaped structure with a characteristic “face” appearance due to the presence of two nuclei and other internal structures. (C) Eggs of Strongyloid Small, oval-shaped eggs with a smooth outer shell, and containing larvae.

Fig. 1.

Fig. 2.

Fig. 3.

Fig. 4.

Fig. 5.

Depending on the observations from figure 6, the microscopic examination revealed the following egg characteristics: (A) Moniezia benedeni (Cestode tapeworm) eggs were large oval eggs with a thick outer membrane, an oncosphere visible inside, and typically measured 80 – 100 μm in length by 60 – 80 μm in width. (B) Paramphistomum cervi (Ruminal fluke) eggs were operculated eggs with a small lid or cap at one end, measuring typically 140 – 150 μm by 90 – 100 μm, and containing a fully developed miracidium when laid. (C) Haemonchus spp. eggs were barrel-shaped rather than oval, with a thin outer membrane, measuring around 70 – 90 μm in length by 40 – 50 μm in width, and may have had a visible larva inside.

The prevalence of infected camels with Trichostrongylus spp. depends on the polymerase chain reaction (PCR) technique

The PCR test results shown that 45.5 % (30/66) of the samples were positive for Trichostrongylus spp. and observing a clear bands at 250bp target size. Breakdown of Positive Bands showed positive bands were scored using band intensity relative to the each other. 15 samples had band intensities ≥80 %, 10 samples between 50 – 70 % intensity, and 5 samples showed faint bands <50 % intensity. Sequencing Confirmation using 12 positive PCR products sequenced via Sanger sequencing and BLAST analysis indicated >98 % homology to reference Trichostrongylus sequences for 10 samples, while 2 samples showed 95 % and 92 % homology, indicating genus-level confirmation (Fig. 7).

Fig. 6.

Fig. 7.

In this study, the percentage of infection with various intestinal parasites reached 88.5 %. This result is agrees with (Karawan, 2017), which reported a percentage rate of 86.36 % of internal parasites in camels in Iraq (Demelash et al., 2014), recorded a percentage of 80.73 % of harbouring different gastrointestinal parasites in camels in Ethiopia. In Pakistan’s Faisalabad Abattoir, results reported by (Anwar & Hayat, 1998) were also close to 69.1 % for camels.

Additionally, testing in the Yabello district, southern Ethiopian rangelands, revealed that 73.8 % of the camels had discharged protozoan oocysts or helminth eggs in their faces (Duguma et al., 2014). While Birhanu et al. (2014) (Birhanu et al., 2014) noted a proportion of 55.5 % in different pastoral areas of Ethiopian. In Iran, the prevalence rate of gastrointestinal helminthes was 52 % that reported in Bactrian camels (Tajik et al., 2011), mostly indicated by the presence of helminthe eggs. As well as in Riyadh, Saudi Arabia, 19 camels were reported to have internal parasites, which are reported to be positive in 59.6 % of cases (Al-Megrin, 2015). An infection rate of gastrointestinal parasites of 48.26 % in camels in Algeria was revealed by microscopic examination, which was recorded by (Bouragba et al., 2020). Additionally, 50.3 % of camels had gastro-intestinal parasites in Somalia (Ibrahim et al., 2016). In Egypt, 60 % of camels had parasitic infections (El-Khabaz et al., 2019).

Protozoal infection in this study was 29 %, which was less than recorded by Hasan et al. (2021), in northern Iraq. While similar to the study of Bouragba et al. (2020), who reported that protozoal infection in Algerian camels was 17.02 %.

The current study found that camels had a 15 % cestode infection rate, which is consistent with the Pakistani reported incidence (22.5 %). However, it disagrees with the rate identified in camels in Somalia (6.0 %) (Ibrahim et al., 2016; Mahfooz et al., 2006) (Mahfooz et al., 2006).

In this investigation, similar to rate in Pakistanian and Somalian camels, 2 % of camels were found to be infested by trematodes (Anwar & Hayat, 1998; Ibrahim et al., 2016).

In the present research, the percentage of Trichostrongylidae spp. that detected by microscopical examination was 33 %, which is consistent with the results achieved by (Anwar & Hayat, 1998). Furthermore, the percentage of Trichostrongylus spp. was corresponded to that reported for camels in Egypt (38.8 %) (El-Khabaz et al., 2019). Additionally, our performance percentage is lower than that recorded in province of Nineveh in Iraq (49 %) (Hasan et al., 2021), but higher than India (10.71 %) (Rewatkar et al., 2009). Moreover, the proportion of infestation of camels in China is 98.1 % (Guowu et al., 2020). While 79.67 % and 75 % in southern and eastern Ethiopia, respectively (Bekele, 2002).

According to PCR analysis, the positive value of Trichostrongylus is high. It is 45.5 % (60 out of 300). Our results are consistent with Pathak and Chhabra (2010) who reported 26 % for Trichostrongylus axei and 65.2 % for Trichostrongylus colubriformis in camels using the PCR-RFLP technique. In another study, 54.44 % were found positive for Trichostrongylus in PCR analysis (El-Alfy et al., 2019; Bakooie Katrimi et al., 2022). Additionally, 31.45 % of goats in Bangladesh tested positive for Trichostrongylus (Ahmed et al., 2022). In Iran, 1.8 % of Trichostrongylus isolates were recorded in the abomasum and small intestine of sheep and goats (Ghatee et al., 2020).

Also Pilarczyk et al. (2021) showed that Trichostrongylus eggs are also the most common pathogen infecting ruminants, followed by Trichuris spp. Additionally, Ashrafi et al. (2020) demonstrated that various of Trichostrongylus species, including T. colubriformis, T. vitrinus, and T. orientalis are zoonotic nematodes that are widely distributed among herbivores worldwide. The presence of genus such as Nematodes, Fascioliosis and Moniezia shows that camels are sensitive to various internal diseases (Locklear et al., 2021). According to the findings of the research, the disease affected camels depending on the ecology of different organisms, environment, mixing with other animal species, and culture of human poulation (Osman, 2014). These findings emphasize the importance of camel diseases for animal and human health (Elmahallawy et al., 2023; Thamsborg et al., 2017).

The present Study show that nematodes are the most common type of parasite, followed by protozoan oocysts and tapeworms. Many species such as Trichostrongylus, nematodes, Fasciola and Moniezia have been found to cause disease in camels. In microscopic examination, Trichostrongylus spp. is the main species with a standard detection rate of 33 %. The 33 % of Trichostrongylus spp. samples were confirmed by PCR tests showed that the positive was percentage 45.4 % (30 out of 66 samples). These results highlight the importance of combating parasites in camels because they have significant clinical, public health and financial implication and all factors contribute to the overall health and well-being of camels and humans.