acuaria hamulosa ) , is a species of acuariidae family and etiological agent of cheilospirurosis in birds such as chickens , turkeys , pigeons , and guinea fowls [ 1 , 2 ] .
cheilospirura hamulosa has cylindrical body with two triangular lips and 4 cuticular cordons that extend near posterior extremity .
the c. hamulosa is located under gizzard cuticle mainly in koilin or muscular wall of the host [ 1 , 2 ] .
this nematode has indirect life cycle . the grasshoppers ( melanoplus , oxyanitidula , and spathosternum parasinifrum ) , beetles , and weevils are intermediate hosts for c. hamulosa and birds acquire their infections by eating contaminated arthropods containing infective third - stage larvae . due to its high pathogenicity in poultry , the c. hamulosa has veterinary and public health importance .
cheilospirura hamulosa can cause several complications such as granulomas and nodules that lead to anemia , impotence , and mortality in chickens .
cheilospirura hamulosa may cause zoonosis and has been recovered from a nodule on the conjunctiva of a filipino farmer .
the previous studies in rural areas of iran indicated that the infection of this worm is common among free - range chickens , whereas there is no published data on partridges in iran .
the main goal of the present study was to survey prevalence of cheilospirura hamulosa infection in partridges ( alectoris chukar ) using morphological - based methods , in taleqan county of iran .
this area is located in alborz province and its height is 1900  m above the sea level . latitude and longitude of taleqan are 36 degrees 15n and 50 degrees 46e , respectively .
every year from the end of september to the beginning of february a license is issued by the environment protection agency ( epa ) of iran for hunting partridges .
every hunter has permission to hunt the maximum of three partridges weekly . for this research ,
the gizzard of each partridge was removed from the alimentary tract and delivered to the helminthology laboratory of shahid beheshti university of medical sciences .
the gizzards were examined macroscopically and then dissected in a 0.85% nacl solution ( normal saline ) to remove cuticle .
the worms were rinsed in normal saline and fixed in alcohol - glycerin ( 70% alcohol , 50  ml ; glycerin , 50  ml ) solution .
helminthes were counted and identified under light microscopy ( zeiss , germany ) and stereoscopic microscope ( zeiss , germany ) and traced by camera lucida ( zeiss , germany ) .
the morphological identification of the nematodes to the species level was done according to methods described by skrjabin et al . .
out of a total of 100 partridges examined , the prevalence of c. hamulosa was 30% with a mean intensity of 3.9% and range of infection of 112 .
a total of 116 worms were recovered from partridges . among the recovered helminthes , 60.3% were female and 39.7% male .
the specimens of c. hamulosa were found free under the gizzard cuticle , partially or fully burrowed in the walls ( figure 1 ) .
microscopic description was based on 10 adult worms , five males and five females ( table 1 ) .
the average length of adult males was 12.2  0.67  mm and their average width was 0.3  0.06 .
the mean of cordons length was 9.2  0.28 , ratio between cordons and body length was 1  :  1.33 ( figure 2 , ( a1)(a3 ) ) , long spicule slender was 1.44  0.08  mm in length , short spicule shaped like a chopping knife was 0.62  0.11  mm long , and ratio between long and short spicules was 1  :  2.3 .
the ratio between mean of long and short spicules length and body length were 0.11  mm and 0.04  mm , respectively .
the mean length of caudal alae was 0.42  0.02 and its width was 0.32  0.02 , with tail 0.43  mm long ( n = 1 ) . in each worm
there were ten pairs of caudal papillae : three couples were observed in precloacal , two pairs in adcloacal , and five couples in postcloacal ( figure 2 , ( b1)(b3 ) ) .
the mean length and width of females were 17.5  2.14 and 0.39  0.04  mm , respectively .
the mean of cordon length was 12.96  0.72 , and ratio between cordons and body length was 1  :  1.68 .
the females were amphidelphic , and their vulva is located slightly posterior to the middle of the body at 2.29  0.92 from the posterior end , circular sphincter 0.064  0.065 , tail 0.44 ( n = 1 ) long ( figure 3 , ( a1)-(a2 ) and ( b1)-(b2 ) ) .
embryonated eggs were 0.0450.055 ( 0.051 ) long and 0.0280.03 ( 0.029 ) wide ( figure 4 ) .
the nematode c. hamulosa reported herein is reported for the first time from partridges in iran .
the partridge ( alectoris chukar ) is the most important bird hunted in iran . in the present study ,
prevalence of c. hamulosa in the partridge was 30% with a mean intensity of 3.9% and range of infection of 112 .
the reported prevalence of this nematode by menezes et al .   in brazil was 14.3% in ring - necked pheasants ( phasianus colchicus ) with a mean intensity and range of infection of 1.5 , 1 - 2 , respectively .
in domestic chickens ( gallus g. domesticus ) , the prevalence , mean intensity , and range of infection were 26.7% , 4 and 112 , respectively . a 2-year study in kashmir , india , on the prevalence of the nematode c. hamulosa in indigenous fowl
the prevalence of c. hamulosa in guinea fowls ( numida meleagris galeata pallas ) from ghana and chickens in zimbabwe and cuba was 37.8% , 46.6% , and 84.6% , respectively [ 1113 ] .
the reported prevalence of c. hamulosa on native fowls from golestan province in north of iran was 4% which is significantly lower than our result , because the study population is completely different from our study .
the nematodes of the genus acuaria ( cheilospirura ) are parasitic among different families of birds and they are located under the koilin layer usually in the cardiac or pyloric regions . also in our study the specimens of c. hamulosa were found under the gizzard cuticle , partially or fully burrowed in the walls of the organ ( figure 1 ) .
most of the reported lengths for male and female c. hamulosa are within the range of 914 and 1525 , respectively ( [ 3 , 14 ] and [ 1 , 7 , 8 ] ) ( table 1 ) . in this study ,
male worms were smaller than the female worms in average body length , overall cordon , glandular oesophagus , and muscular oesophagus length ( table 1 ) .
moreover , in our study , the long spicules were smaller and the length of short spicules was longer compared with previous studies reported by cram [ 1 , 3 ] , yamaguti , and gomes et al .  
average length of male worms was higher than those reported by gomes et al . . in our study ,
the female worms were smaller in maximum body length than those described by cram and yamaguti [ 3 , 7 ] but still were bigger than those described by gomes et al . .
the female of c. hamulosa in our study had smaller muscular and glandular oesophagus than those reported by gomes and yamaguti [ 7 , 8 ] , whereas values obtained for the length of tail and egg size were bigger compared to two studies mentioned above ( table 1 ) .
we observed 10 pairs of papillae in c. hamulosa as reported by cram   and gomes et al .
; however , in the precloacal region , 2 pairs of papillae were unclear ( figure 2 , ( b1)(b3 ) ) . due to the significant pathogenic effects of these nematodes ( cheilospirura spp . ) in poultry and wild bird population and very limited prevalence data of these helminthes in iran , further study will be needed on different aspects of acuarioidea family including pathogenesis and their prevalence in other avian species .
in the present study , we report for the first time the isolation and morphological characterization of cheilospirura hamulosa from partridges in iran . the morphological characters described in this study
 this study reports data on the prevalence , morphology , and morphometry of the nematode cheilospirura hamulosa on the basis of light and stereoscopic microscopy and also camera lucida . 
 specimens were recovered after necropsies of 100 partridges ( alectoris chukar ) from taleqan county in alborz province , iran . 
 the prevalence of c. hamulosa in partridges was of 30% with a mean intensity of 3.9 and range of infection of 112 . 
 the mean length and width of females were 17.5  2.14 and 0.39  0.04  mm , while those of males were 12.2  0.67 and 0.3  0.06  mm , respectively . 
 the characteristic digitiform tail was observed in females , and the unequal spicules , caudal alae , and ten pairs of caudal papillae were seen in males . 
 the taxonomic characteristic longitudinal cordons and muscular and glandular oesophagus were observed in both sexes . 
 ratio between cordons and body length in males and females was 1  :  1.33 and 1  :  1.68 , respectively . 
 ratio between long and short spicules in males was 1  :  2.3 . 
 the average size of embryonated eggs was 51.25  29.5  m . in the present study , c. hamulosa ( nematoda : acuarioidea ) 
 is recorded for the first time from partridges in iran . 
 therefore , the morphological characters described in this study will be useful in the future diagnostic and taxonomic studies of acuarioidea family . 