Pinworms are routinely found in animals from modern animal facilities, even in facilities free of viral and bacterial diseases that affect mice (Jacoby and Lindsey, 1998; Zenner and Regnault, 2000; Behnke et al., 2015). Oxyurids are also a common parasite of Muroidea (Rodentia) (Singleton et al., 1993; Pisanu et al., 2001).
The genus
Species of
Therefore, the present study reported the natural prevalence, morphological, and morphometric characteristics, in addition to molecular analysis of ribosomal DNA gene sequences of the recovered oxyurid pinworm infecting the laboratory mouse
Fifty specimens of adult laboratory mice (Muridae:
gDNA was extracted from ethanol-preserved samples using DNeasy tissue kit© (Qiagen, Hilden, Germany) following the manufacturer’s instructions. The DNA was stored in 50 μl of TE buffer at −20°C until further use. DNA concentration and purity were determined spectrophotometrically by measuring absorbance at wavelengths of 260 and 280 nm. PCR amplification was performed in a final volume of 25 µl, containing 3 μl of genomic DNA, 2.5 μl of 10X Taq polymerase buffer, 10 pmol of each primer, 100 μM of each dNTP (Finnzymes Products), and 1.5 U of Taq DNA polymerase (Finnzymes Products). The partial ribosomal 18S gene was amplified using the primer Nem 18SF (5′-CGC GAA TRG CTC ATT ACA ACA GC-3′) and Nem 18SR (5′-GGG CGG TAT CTG ATC GCC-3′) designed by Floyd et al. (2005). Polymerase chain reaction (PCR) consisted of an initial denaturation step at 94°C for 3 min, followed by 35 cycles of 1 min at 94°C, 1 min at 50°C, followed by 1 min at 72°C, and finally, post-PCR extension was carried out for 7 min at 72°C. All PCR products were verified on 1% agarose gel in ×1
BLAST search was carried out to identify related sequences on NCBI database. Sequences were aligned directly using CLUSTAL-X multiple sequence alignment (Thompson et al., 1997) and compared with previously recorded data from GenBankTM to analyze intra-specific differences. GenBank accession numbers of additional sequences utilized in the analyses were as follows:
Nematoda species used in the phylogenetic analysis of
Parasite species | Order/family | Host species | Source | Accession no. | Sequence length (bp) | Divergence | Percent identity (%) |
---|---|---|---|---|---|---|---|
Ascaridida/Cosmocercidae | GenBank | LC052782 | 749 | 5.2 | 89.0% | ||
Ascaridida/Ascarididae | Africa lion and wolf | GenBank | JN617987 | 814 | 5.2 | 89.0% | |
Rhabditida/Cucullanidae | GenBank | KT192060 | 1,150 | 4.9 | 90.0% | ||
Rhabditida/Acanthocheilidae | Elasmobranchs | GenBank | JN392470 | 903 | 4.9 | 90.0% | |
Oxyurida/Oxyuroidae | Human children | GenBank | HQ646164 | 2,867 | 5.2 | 91.0% | |
Oxyurida/Oxyuroidae | GenBank | AB699691 | 898 | 4.9 | 91.0% | ||
Oxyurida/Heteroxynematidae | GenBank | KT175733 | 967 | 3.2 | 92.0% | ||
Oxyurida/Heteroxynematidae | GenBank | KT175725 | 936 | 1.4 | 97.0% | ||
Oxyurida/Heteroxynematidae | GenBank | KT175736 | 995 | 0.6 | 98.0% | ||
Oxyurida/Heteroxynematidae | GenBank | KT175728 | 954 | 0.6 | 98.0% | ||
Oxyurida/Heteroxynematidae | GenBank | KT175729 | 964 | 0.6 | 98.0% | ||
Oxyurida/Heteroxynematidae | GenBank | KJ143615 | 419 | 0.1 | 99.0% | ||
Oxyurida/Heteroxynematidae | GenBank | KJ143618 | 419 | 0.1 | 99.0% | ||
Oxyurida/Heteroxynematidae | GenBank | KJ143617 | 419 | 0.1 | 99.0% | ||
Oxyurida/Heteroxynematidae | GenBank | KJ143616 | 419 | 0.1 | 99.0% | ||
Oxyurida/Heteroxynematidae | GenBank | EF464551 | 3,676 | 0.1 | 99.0% | ||
Oxyurida/Heteroxynematidae | GenBank | EU263107 | 1,032 | 0.1 | 99.0% |
A total of 28 out of 50 (56.0%) specimens of laboratory mice
In general, the body of the recovered worms was small, cylindrical in shape, and covered by a transversely striated cuticle. Head was bulb-like; mouth opening was surrounded by three less developed lips, one pair of lateral epaulettes, one pair of amphidial pores, and two pairs of large sub-median cephalic papillae. Mouth opening leads to the buccal cavity, followed by pharynx, esophagus, and long intestine opening exteriorly by an anal opening in females and cloacal opening in males. Anterior part of esophagus was club-shaped followed by well-developed bulb. Body in both sexes has distinct cervical alae, beginning immediately posterior to the anterior end of the cephalic vesicle. Cervical alae abruptly interrupted at the level of esophago–intestinal junction, forming an acute angle. Anterior end of the body has prominent, elaborate inflated region, forming cephalic vesicle (Fig. 1A–G, Tables 2,3).
Main morphological features and measurements of male
Related species | |||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Parameters | Kruidenier and Mehra (1959) | Araujo (1965) | Hugot (1980) | Hugot (1980) | Miller and Schmidt (1982) | Kohn and Macedo (1984) | Pinto et al. (1994) | Landaeta-Aqueveque et al. (2007) | Falcón-Ordaz et al. (2010) | Liu et al. (2012) | Khalil et al. (2014) | Abdel-Gaber and Fol (2015) | (Present study) |
Host species | |||||||||||||
Host locality | Coconimo, Arizona | Sao Paulo, Brazil | Onderstepoort, South Africa | Maracay, Venezuela | Colorado, Idaho, USA | Rio de Janeiro, Brazil | Río de Janeiro, Brazil | Santiago, Chile | Hidalgo, Mexico | Tianjin, China | Cairo, Egypt | Cairo, Egypt | |
Site of infection | Intestine | Intestine | Caecum | Caecum | Caecum | Intestine | Intestine | Caecum and upper colon | Intestine | Intestine | Caecum | Caecum | Caecum and upper colon |
Body length | 4.41–4.87 (4.64) | 2.945–3.472 | 1.59 | 2.7 | 3.01–6.35 (5.03) | 2.90–3.60 (3.22) | 2.4–3.1 | 2.65–3.95 (3.393 ± 0.427) | 2.16–2.69 (2.48 ± 0.172) | 3.69– 5.12 (4.69) | 2.55–2.57 (2.56 ± 0.014) | 2.73–3.87 (3.21 ± 0.1) | 2.23–3.29 (2.79 ± 0.1) |
Body width | 0.162–0.174 (0.168) | 0.156–0.180 | 0.10 | 0.11 | 0.137–0.293 (0.236) | 0.15–0.20 (0.17) | 0.17–0.21 | 0.17–0.25 (0.202 ± 0.2) | 0.078–0.114 (0.096 ± 0.01) | 0.204–0.388 (0.307) | 0.088 (0.088 ± 0) | 0.18–0.23 (0.20 ± 0.1) | 0.16–0.20 (0.18 ± 0.1) |
Esophageal length | 0.264–0.271 (0.267) | 0.213–0.243 | 0.310 | 0.38 | 0.260–0.480 (0.343) | 0.18–0.27 (0.23) | 0.288–0.360 | 0.320–0.390 (0.375 ± 0.02) | 0.291–0.294 (0.272 ± 0.013) | 0.343–0.397 (0.384) | 0.439–0.450 (0.44 ± 0.007) | 0.38–0.45 (0.41 ± 0.1) | 0.32–0.40 (0.39 ± 0.1) |
Esophageal width | 0.039–0.040 (0.039) | 0.036–0.054 | – | – | 0.033–0.060 (0.051) | – | – | – | – | – | – | 0.06–0.11 (0.08 ± 0.01) | 0.05–0.09 (0.07 ± 0.01) |
Esophageal bulb length | 0.145–0.155 (0.150) | 0.105–0.135 | 0.10 | 0.14 | 0.113–0.183 (0.157) | 0.10-0.12 (0.11) | – | 0.110–0.140 (0.133 ± 0.01) | 0.090–0.110 (0.097 ± 0.006) | 0.074–0.142 (0.122) | 0.244 (0.24 ± 0) | 0.14–0.19 (0.16 ± 0.1) | 0.13–0.17 (0.15 ± 0.1) |
Esophageal bulb width | 0.071–0.079 (0.075) | 0.075–0.096 | 0.08 | 0.09 | 0.065–0.120 (0.090) | 0.06–0.08 (0.07) | – | – | 0.040–0.063 (0.051 ± 0.006) | 0.059–0.123 (0.098) | 0.077–0.088 (0.08 ± 0.007) | 0.07–0.09 (0.08 ± 0.01) | 0.04–0.07 (0.05 ± 0.01) |
Distance from anterior extremity Nerve ring | 0.158 | 0.108–0.144 | 0.09 | 0.10 | 0.150–0.213 (0.186) | 0.11–0.13 (0.12) | 0.115–0.140 | 0.115–0.145 (0.129 ± 0.013) | 0.072–0.093 (0.080 ± 0.008) | 0.116–0.133 (0.123) | 0.088 (0.088 ± 0) | – | 0.065–0.082 (0.078 ± 0.001) |
Excretory pore | – | 0.600–0.876 | 0.325 | 0.78 | 0.69–1.21 (0.96) | 0.69–0.78 (0.73) | 0.619 | 0.750 –0.910 (0.854 ± 0.056) | 0.495–0.579 (0.545 ± 0.035) | 0.93–1.03 (1.01) | 0.144–0.147 (0.145 ± 0.002) | – | 0.392–0.547 (0.491 ± 0.03) |
No. of Caudal papillae | 11 | 5 | 5 | 5 | 10 | 12 | 12 | 12 | 12 | 12 | 12 | 12 | 12 |
Tail length | 0.238–0.280 (0.259) | 0.147–0.183 | 0.12 | 0.17 | 0.049–0.117 (0.092) | 0.10-0.12 (0.11) | 0.144–0.172 | 0.162–0.187 (0.178 ± 0.009) | 0.075–0.114 (0.102 ± 0.013) | 0.181–0.245 (0.220) | 0.12–0.144 (0.132 ± 0.01) | 0.13–0.15 (0.14 ± 0.1) | 0.11–0.14 (0.12 ± 0.1) |
Main morphological features and measurements of female
Related species | |||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Parameters | Kruidenier and Mehra (1959) | Araujo (1965) | Hugot (1980) | Hugot (1980) | Miller and Schmidt (1982) | Kohn and Macedo (1984) | Pinto et al. (1994) | Landaeta-Aqueveque et al. (2007) | Falcón-Ordaz et al. (2010) | Liu et al. (2012) | Khalil et al. (2014) | Abdel-Gaber and Fol (2015) | (Present study) |
Host species | |||||||||||||
Host locality | Coconimo, Arizona | Sao Paulo, Brazil | Onderstepoort, South Africa | Maracay, Venezuela | Colorado, Idaho, USA | Rio de Janeiro, Brazil | Río de Janeiro, Brazil | Santiago, Chile | Hidalgo, Mexico | Tianjin, China | Cairo, Egypt | Cairo, Egypt | Cairo, Egypt |
Site of infection | Intestine | Intestine | Caecum | Caecum | Caecum | Intestine | Intestine | Caecum and upper colon | Intestine | Intestine | Caecum | Caecum | Caecum and upper colon |
Body length | 5.5–6.8 (6.2) | 3.534–5.394 | 1.95 | 1.2 | 5.46–8.97 (7.41) | 3.60–4.61 (4.18) | 3.1–3.6 | 3.53–4.51 (3.53–4.51) | 3.024–3.528 (3.219 ± 0.150) | 5.38–7.00 (6.46) | 3.55–4.12 (3.83 ± 0.403) | 3.2–3.6 (3.5 ± 0.1) | 2.9–3.4 (3.1 ± 0.1) |
Body width | 0.197–0.232 (0.210) | 0.153–0.234 | 0.15 | 0.08 | 0.225–0.391 (0.330) | 0.20–0.30 (0.27) | 0.175–0.245 | 0.230–0.270 (0.260 ± 0.01) | 0.099–0.153 (0.120 ± 0.016) | 0.282–0.447 (0.352) | 0.199–0.288 (0.244 ± 0.062) | 0.21–0.26 (0.24 ± 0.01) | 0.19–0.23 (0.20 ± 0.01) |
Esophageal length | 0.290–0.348 (0.317) | 0.252–0.336 | 0.49 | 0.43 | 0.305–0.465 (0.387) | 0.25–0.29 (0.27) | 0.331–0.433 | 0.400–0.450 (0.425 ± 0.01) | 0.312–0.351 (0.322 ± 0.012) | 0.417–0.480 (0.461) | 0.328–0.382 (0.35 ± 0.038) | 0.33–0.39 (0.27 ± 0.01) | 0.30–0.34 (0.32 ± 0.01) |
Esophageal width | 0.042–0.052 (0.044) | 0.048–0.057 | – | – | 0.045–0.080 (0.061) | – | – | – | – | – | – | 0.17–0.19 (0.18 ± 0.01) | 0.14–0.16 (0.15 ± 0.01) |
Esophageal bulb length | 0.145–0.171 (0.158) | 0.129–0.159 | 0.14 | 0.16 | 0.150–0.225 (0.177) | 0.12–0.15 (0.13) | – | 0.140–0.160 (0.152 ± 0.006) | 0.090–0.111 (0.103 ± 0.005) | 0.123–0.167 (0.152) | 0.108 (0.108 ± 0) | 0.12–0.15 (0.140 ± 0.01) | 0.10–0.13 (0.11 ± 0.01) |
Esophageal bulb width | 0.068–0–0.087 (0.080) | 0.087–0.111 | 0.095 | 0.13 | 0.080–0.150 (0.107) | 0.08–0.12 (0.10) | – | – | 0.054–0.087 (0.063 ± 0.008) | 0.088–0.137 (0.118) | 0.081 (0.081 ± 0) | 0.07–0.11 (0.09 ± 0.01) | 0.05–0.09 (0.07 ± 0.01) |
Distance from anterior extremity Nerve ring | 0.155–0.185 (0.168) | 0.120–0.168 | 0.14 | 0.13 | 0.162–0.238 (0.202) | 0.15 | 0.158–0.216 | 0.12–0.162 (0.140 ± 0.013) | 0.081–0.0105 (0.093 ± 0.007) | 0.121–0.157 (0.134) | 0.144–0.147 (0.145 ± 0.002) | – | 0.078–0.090 (0.085 ± 0.002) |
Excretory pore | – | 0.756–1.056 | 0.53 | 0.9 | 0.82–1.67 (1.10) | 0.81–0.89 (0.86) | 0.734–0.936 | 0.860–0.950 (0.888 ± 0.032) | 0.555–0.675 (0.590 ± 0.038) | 1.09–1.23 (1.17) | – | – | 0.564–0.780 (0.680 ± 0.02) |
Vulval opening | 2.1–2.5 (2.3) | 1.457–2.015 | 0.85 | 1.65 | 1.52–2.89 (2.49) | 1.54–2.36 (1.76) | 1.1–1.4 | 1.61 ± 0.038 (1.55–1.67) | 1.204–1.428 (1.269 ± 0.066) | 2.07–2.43 (2.27) | 1.56–1.86 (1.71 ± 0.21) | – | 1.112–1.630 (1.406 ± 0.03) |
Tail length | 0.232–0.690 (0.445) | 0.444–0.660 | 0.435 | 0.55 | 0.088–0.110 (0.101) | 0.36–0.40 (0.39) | 0.360–0.486 | 0.347–0.537 (0.477 ± 0.06) | 0.330–0.372 (0.358 ± 0.016) | 0.92–1.14 (1.05) | 0.382–0.405(0.393 ± 0.016) | 0.34–0.48 (0.42 ± 0.01) | 0.30–0.42 (0.39 ± 0.01) |
Eggs length | 0.097–0.106 (0.101) | 0.084–0.090 | 0.09 | 0.095 | 0.093–0.110 (0.102) | 0.075–0.090 (0.084) | 0.72–0.90 | 0.084–0.092 (0.087 ± 0.005) | 0.054–0.069 (0.061 ± 0.003) | 0.092–0.096 (0.094) | 0.115–0.129 (0.122 ± 0.008) | 0.05–0.07 (0.06 ± 0.01) | 0.04–0.06 (0.05 ± 0.01) |
Eggs width | 0.0390.047 (0.044) | 0.036–0.039 | 0.04 | 0.045 | 0.038–0.055 (0.045) | 0.038–0.051 (0.045) | 0.036 –0.053 | 0.043–0.052 (0.046 ± 0.005) | 0.018–0.030 (0.022 ± 0.003) | 0.051–0.058 (0.054) | 0.054–0.072 (0.06 ± 0.008) | 0.03–0.05 (0.04 ± 0.01) | 0.02–0.04 (0.03 ± 0.01) |
Body length was 2.23–3.29 (2.79 ± 0.1) mm with maximum width 0.16–0.20 (0.18 ± 0.1) mm. Cephalic vesicle was 0.06–0.09 (0.07 ± 0.001) mm long by 0.05–0.08 (0.06 ± 0.001) mm wide. Esophagus measured 0.32–0.40 (0.39 ± 0.1) mm long by 0.05–0.09 (0.07 ± 0.01) mm wide; while, the whole esophagus with bulb reached 0.13–0.17 (0.15 ± 0.1) mm long by 0.04–0.07 (0.05 ± 0.01) mm wide. Cervical alae began at 0.015–0.018 (0.017 ± 0.001) mm from the anterior end and measured about 0.21–0.29 (0.25 ± 0.001) mm long with recurved terminal ends by 0.029–0.038 (0.031 ± 0.001) mm wide. Nerve ring and excretory pore are located at 0.065–0.082 (0.078 ± 0.001) mm and 0.392–0.547 (0.491 ± 0.03) mm from the anterior end, respectively. Narrow lateral alae of the body end located at the beginning of the caudal alae are extended from the level of cloaca and surrounded the entire end of the body, bending ventrally at its tip as a vesicular swelling of the cuticle. Cloaca opening is located at 0.09–0.11 (0.10 ± 0.01) from the posterior extremity of the body. Testes are flexed over the anterior third of the intestine. Gubernaculum and spicules were absent. Posterior end with 12 caudal papillae included one pair precloacal, two pairs adcloacal, one pair postcloacal, two median papillae postcloacal, one behind the other, and a further posterior pair midway between cloaca and end of the tail. Tail, with blunt end, measured 0.11–0.14 (0.12 ± 0.1) mm long.
Body length was 2.9–3.4 (3.1 ± 0.1) mm long with maximum width was 0.19–0.23 (0.20 ± 0.01) mm. Cephalic vesicle reached about 0.078–0.083 (0.082 ± 0.001) mm long by 0.106–0.130 (0.123 ± 0.01) mm wide. Esophagus measured 0.30–0.34 (0.32 ± 0.01) mm long and 0.14–0.16 (0.15 ± 0.01) mm wide; while, esophagus with bulb reached about 0.10–0.13 (0.11 ± 0.01) mm long and 0.05–0.09 (0.07 ± 0.01) mm wide. Nerve ring and excretory pore located at 0.078–0.090 (0.085 ± 0.002) mm and 0.564–0.780 (0.680 ± 0.02) mm from the anterior end, respectively. Cervical alae with recurved terminal end was 0.27–0.29 (0.26 ± 0.01) mm long. Distance from the anterior end to the beginning of cervical alae was 0.021–0.026 (0.024 ± 0.001) mm. Vulva was preequatorial, surrounded by protruded lips, and situated at 1.112–1.630 (1.406 ± 0.03) mm from the anterior extremity of the body. Ovejector apparatus measured about 0.29–0.38 (0.32 ± 0.01) mm long. Muscular vagina proceeded forward for a short distance then turned backward joining uterus filled with eggs. Two ovaries flexed over the proximal part of the intestine. Anal pore located at 0.32–0.39 (0.37 ± 0.01) mm from the posterior end of the body. Tail with blunt tip measured 0.30–0.42 (0.39 ± 0.01) mm long. Eggs were unoperculated, smooth, filled by morula and measured 0.04–0.06 (0.05 ± 0.01) mm long and 0.02–0.04 (0.03 ± 0.01) mm wide.
Parasite name:
Host: Laboratory mice
Mode of transmission: Ingestion of embryonated eggs in feces, or in contaminated food and water, or bedding.
Morbidity and mortality: Infected laboratory mice were generally symptomless externally.
Site of infection: Cecum and upper colon of infected host mice.
Prevalence and intensity: 28 out of 50 (56.0%) examined individuals were infected, with a total number of 120 nematodes.
Material deposition: Voucher specimens were deposited at museum in Zoology Department, Faculty of Science, Cairo University, Cairo, Egypt.
A sequence of 840 bp was deposited in GenBank under accession no. MG019400 with a GC content of 42.26%, for SSU rDNA gene sequences of the present oxyurid species. Pairwise comparison of the isolated gDNA sequence of the present parasite species with a range of other Spirurina species and genotypes revealed a unique sequence. The calculated identity between this novel sequence and those retrieved from GenBank demonstrated a high degree of similarity, up to 88.0% (Table 1). Comparison of the nucleotide sequences and divergence showed that SSU rDNA of the present oxyruid species had the highest blast scores with a small number of nucleotide differences with other
Phylogenetic analysis led to the construction of a neighbor-joining tree, constructed with partial sequences, which showed that Spirurina species consistently formed two major clades (Fig. 2). The first one represented the most related families in order Oxyurida, including families Heteroxynematidae and Oxyuridae with sequence similarity ranging between 99.0 and 91.0%. The second one was represented by four families Ascarididiae (
Laboratory animal models, especially rodents of the family Muridae, constitute important links in the food chains within the ecosystems they inhabit (Rosas, 1997, Gonçalves et al., 1998). These animals are often in contact with humans and domestic animals and can transmit various parasitic species (Bazzano et al., 2002). In conventional animal facilities, rodent colonies are frequently infected with helminth parasites, or become infected during the experimental period (Sato et al., 1995, Rehbinder et al., 1996). Oxyurids are cosmopolitan nematoda parasites of public health importance (Khalil et al., 2014). The order Oxyurida includes three families namely Oxyuridae (Cobbold, 1864); Pharyngodonidae (Travassos, 1919); and Heteroxynematidae (Skrjabin and Schikhobalova, 1948). Nematodes from the genera
Based on morphological characters, the oxyurid species described here showed the characteristic features of the genus
The present parasite species was compared morphologically and morphometrically with other
Due to close morphological similarities, molecular phylogenetic approaches have been used extensively in association with traditional morphological techniques as reliable methods for confirmation of accurate identification, and differentiation between pinworms infecting laboratory rodents (Jacobs et al., 1997; Zhu et al., 1998; Vermund and Wilson, 2000; Morales-Hojas et al., 2001; Nakano et al., 2006; Li et al., 2007; Zhu et al., 2007; Chang et al., 2009). In the present study, a nuclear rDNA region of the recovered parasite species was amplified using the species-specific primers Nem 18SF/Nem 18SR, designed by Floyd et al. (2005). It is apparent that, the phylogenetic tree based on nuclear SSU rDNA sequences estimated in this study supported strongly the higher taxonomic groups of both orders: Oxyurida (representing the two main families Oxyuridae and Heteroxynematidae) and Ascaridia (representing four families, namely Cosmocercidae, Cucullanidae, Anisakidae, and Ascarididiae). These results are in agreement with data obtained by Blaxter et al. (1998) who reported that clade III of the full dataset of the nematoda phylogeny was represented by all members of the suborder spirurina and clustered into four classical orders of Ascaridia, Oxyurida, Rhigonematida, and Spirurida. Anderson (2000) proposed that Ascaridia and Spirurida were sister groups, which in turn, were more closely related to Strongylida than a group consisting of Oxyurida plus Rhigonematida. Subsequent analyses of SSU rDNA sequences strongly supported the monophyly of clade III taxa with bootstrap values for the clade exceeding 95.0% (De Ley and Blaxter, 2002; Bert et al., 2006; Holterman et al., 2006; Wijová et al., 2006; Qiu et al., 2016; Ribas et al., 2017).
Khalil et al. (2014) reported that the order Oxyurida incorporates three main families, Oxyuridae (Cobbold, 1864); Pharyngodonidae (Travassos, 1919); and Heteroxynematidae (Skrjabin and Schikhobalova, 1948); which was consistent with the results of the current study. In addition, Petter and Quentin (2009) included
Recent field studies have provided useful tools for the rapid identification and phylogenetic analysis of pinworms infecting laboratory rodents. The 18S rDNA gene of
All procedures contributing to this work comply with the ethical standards of the relevant national guides on the care and use of laboratory animals and have been approved and authorized by Institutional Animal Care and Use Committee (IACUC) in Faculty of Science, Cairo University, Egypt (No. CU/I/S/19/16).