Epidemiological, Morphometric, and Molecular Investigation of Cystic Echinococcosis in Camel and Cattle From Upper Egypt: Current Status and Zoonotic Implications

Abstract

Cystic echinococcosis has been considered one of the major parasitic zoonoses which is associated with severe economic losses. The present study was undertaken to investigate the occurrence, organ distribution, cyst fertility, and viability of cystic echinococcosis in slaughtered camels and cattle from various abattoirs in Assiut Governorate, Egypt. The work also involved morphological, morphometric, and molecular identification of the parasite. The occurrence of hydatid cysts was investigated in total number of 100 lungs of camels and 574 liver and lungs of cattle admitted to three slaughterhouses at Assiut Governorate, Egypt. Moreover, several individual variable factors, including organ involvement, age, sex, and hydatid cyst characteristics, were studied to identify their possible association with the occurrence of the disease. Genomic DNA was extracted from the hydatid cysts, followed by molecular identification of the parasite through amplification of ribosomal DNA internal transcribed spacer (ITS) regions. Hydatid cysts were found in 6 camels (6%) out of 100 inspected camels, while 5 hydatid cysts (0.87%) were detected in a total number of 574 cattle examined. The parasite was detected exclusively in lungs of camels, while lungs were the main organ infected by the parasite in cattle and one hydatid cyst was found in the liver (0.17%). In camel, 66.7, 16.65, and 16.65%of detected cysts were fertile, sterile, and calcified, respectively, while in cattle, these percentages were 60, 20, and 20%, respectively. None of the studied variable factors were significantly associated with the occurrence of the disease in camels, with the exception that all cysts were found in the lung. Conversely, we found a significant association (P < 0.05) between the age and sex of the slaughtered cattle and the occurrence of hydatid cysts. In this respect, the rate of infection was higher in female cattle and those cattle more than 5 years (P < 0.05). The morphological, morphometric, and molecular studies confirmed the presence of the parasite. Taken together, our results concluded that camels and cattle play a potential role in maintaining the transmission cycle of this zoonotic parasite.

Keywords: Egypt; camel; cattle; epidemiological; hydatid cyst; molecular; morphometric.

Figure 1

Morphological appearance of Hydatid cyst in the lung of camels. (A) Solitary sterile hydatid cysts. (B) Multiple hydatid cysts. (C) Multiple scolices in viable and non-viable fertile hydatid cyst, using 0.1% Eosin stain (X400) and (D) different-shaped and sized hooks in fertile viable-hydatid cysts.

Figure 2

Morphological appearance of hydatid cyst in lung and liver of cattle. (A) Solitary viable fertile hydatid cysts in the lung of cattle. (B) Multiple scolices in viable fertile hydatid cyst in the lung of cattle using 0.1% eosin stain (X100). (C) Multiple scolices in non-viable fertile hydatid cyst in the lung of cattle using 0.1% eosin stain (X100) and (D) calcified hydatid cysts in the liver of cattle.

Figure 3

Morphometric appearance of small and large hook of hydatid cyst isolated from lung of camel using SEM. (A) The small hook of hydatid cyst. (B) The large hook of hydatid cyst. (C) Measurement the small hook of hydatid cyst; total hook length = 27 μm (arrow), total hook width = 9 μm (arrow), handle length = 9 μm (arrow) and blade length = 10 μm (arrow) and (D) measurement the large hook of hydatid cyst; Total hook length = 34 μm (arrow), total hook width = 12 μm (arrow), handle length = 14 μm (arrow) and blade length = 15 μm (arrow).

Figure 4

Morphometric appearance of small and large hook of hydatid cyst isolated from cattle lung using SEM. (A) The small hook of hydatid cyst isolated from cattle lung. (B) The large hook of hydatid cyst isolated from cattle lung. (C) Measurement the small hook of hydatid cyst isolated from cattle lung; Total hook length = 22 μm (arrow), total hook width = 6 μm (arrow), handle length = 10 μm (arrow) and blade length = 5 μm (arrow) and (D) measurement the large hook of hydatid cyst isolated from cattle lung; total hook length = 28 μm (arrow), total hook width = 8 μm (arrow), handle length = 8 μm (arrow) and blade length = 16 μm (arrow).

Figure 5

Morphometric appearance of hydatid cyst isolated from cattle lung using SEM. (A) SEM of rostellar hooks from protoscoleces of hydatid cyst, isolated from cattle showing alternating large and small hooks, and (B) SEM of brood capsules showing exterior outgrowth in hydatid cyst isolated from a cattle lung (arrow).