Helminth infracommunity in a maned wolf, Chrysocyon brachyurus, from the humid Chaco, Argentina

Parasitism is an important factor in conservation worldwide, especially for endangered species, as it can affect host populations by reducing growth rates, fecundity and affecting nutritional status. The maned wolf Chrysocyon brachyurus, a near-threatened species, is distributed across different habitats from the south Amazonian forest in Brazil to northern Argentina, Paraguay and eastern Bolivia. Most studies on gastrointestinal parasites in wild maned wolves are based on coprological findings, and there is little information about adult parasites and parasite species richness. Therefore, this study aims to expand the knowledge about the helminth infracommunity of a maned wolf, describe adult parasites, and explore parasitic coinfections. We performed a necropsy of an adult individual found road killed in Chaco province, Argentina. We collected adult worms from subcutaneous tissues, from the right ventricle, kidneys, and intestine. The parasites were morphologically identified as Dirofilaria immitis, Dioctophyma renale and Spirometra sp. respectively. To our knowledge, this is the first record for adults of Dirofilaria immitis in maned wolves. Filarioids were located within the heart as well as in subcutaneous tissues with mature females containing uterine microfilariae; this study also adds C. brachyurus as a new host for Spirometra sp. in Argentina. Considering that the three helminths found herein are zoonotic and that the maned wolf is an endangered canid, it is essential provide baseline information to determine the risk factors involved in the transmission and extend the studies to sympatric wild and domestic canids in the area.

Physiological impacts of housing maned wolves (Chrysocyon brachyurus) with female relatives or unrelated males

The maned wolf is a threatened canid species native to South America. Previous studies have suggested the species exhibits induced ovulation. In captive breeding facilities, reproductive success is low while rates of neonatal mortality are high. Females that are not recommended for breeding are frequently housed together. However there has never been a systematic study of the reproductive consequences of co-housing females. This study was conducted for three purposes, to: (1) corroborate the presence of induced ovulation, (2) determine whether elevated cortisol is implicated in neonatal pup mortality, and (3) evaluate the endocrine correlates of group housed females. Using fecal hormone monitoring for estrogen, progesterone, and cortisol, 43 cycles from 33 female maned wolves were studied from 2002 to 2015. Females were categorized by their reproductive status: pregnant and successfully raised pups (PR; n = 11), pregnant with neonatal pup demise within 3 days (PL; n = 7), housed with a male but no signs of breeding or pregnancy (PP; n = 10), housed singly (S; n = 8), or housed with related females (F; n = 7). Estrogen and progestagen remained at baseline for all females not housed with a male (S, F), while elevations consistent with ovulation were seen in females housed with a male (PP, PL, PR). Compared to PR females, PL individuals showed similar cortisol levels throughout the cycle and slightly lower progesterone levels during gestation. As for the effect of co-housing related females, F females showed estrogen and progesterone levels lower even than S females while cortisol levels were elevated compared to all other groups. These findings support the previous evidence of induced ovulation in the maned wolf. Although elevated cortisol does not seem to be implicated in pup loss, a non-significant trend towards lower progesterone during gestation could be implicated. Future studies should assess depressed progesterone levels as a correlate to neonatal pup mortality. Female maned wolves housed with related females experience suppressed reproductive hormones and elevated adrenal hormones. Therefore, a more systematic study of hormonal and behavioral correlates to co-housing with related females is warranted.

Clinical, morphological, and molecular characterization of an undetermined Babesia species in a maned wolf (Chrysocyon brachyurus)

A possible novel Babesia species infection of a maned wolf (Chrysocyon brachyurus) was first reported in 2012. The current case details a confirmed report of a maned wolf with infection by an undetermined species of Babesia. As the mortality and morbidity of babesiosis is high, this may become a significant concern to captive maned wolves, which are considered a near-threatened species by the World Association of Zoos and Aquariums. The aim of this study is to report the clinical, morphological and molecular characterization of this Babesia species. A 2.5-year-old, intact female maned wolf was found laterally recumbent with pale mucous membranes and jaundice the morning of presentation. Hematological and serum biochemical data were consistent with babesiosis and showed a regenerative severe anemia, leukocytosis, thrombocytopenia, hyperbilirubinemia, azotemia, increased creatine phosphokinase and increase alanine aminotransferase. On blood film review, inclusion bodies were seen in the red blood cells with cytomorphological features that were most consistent with a small form Babesia species. A blood sample was sent for polymerase chain reaction (PCR) testing and multi-locus sequence analyses. These findings suggested a unique Babesia species that is most closely related to a Babesia species (Babesia sp. AJB-2006) that has been found to infect raccoons (Procyon lotor) in North America. Although the cytomorphological features of the piroplasms and the clinical presentation were similar in both the current and 2012 case, when comparing the 18S melt curve temperature of the two Babesia isolates, the peak temperature was different. Unfortunately, genetic material from the 2012 case was not available so comparison of multi-locus gene sequences could not be performed, excluding the possibility to definitively state if the Babesia spp. from both cases were distinct from each other. The maned wolf was treated with a whole blood transfusion, dexamethazone (0.28 mg/kg IM), azithromycin (10 mg/kg in NaCl SC), atavaquone (1.5 cc PO), and 2 imidocarb (6.6 mg/kg IM) injections, and clinically improved. These findings demonstrate the need to further characterize the molecular and epidemiological differences of the Babesia species in this case report and the Babesia species known to infect raccoons.

Spermatozoa from the maned wolf (Chrysocyon brachyurus) display typical canid hyper-sensitivity to osmotic and freezing-induced injury, but respond favorably to dimethyl sulfoxide

We assessed the influences of medium osmolality, cryoprotectant and cooling and warming rate on maned wolf (Chrysocyon brachyurus) spermatozoa. Ejaculates were exposed to Ham's F10 medium (isotonic control) or to this medium plus NaCl (350-1000mOsm), sucrose (369 and 479mOsm), 1M glycerol (1086mOsm) or dimethyl sulfoxide (Me2SO, 1151mOsm) for 10 min. Each sample then was diluted back into Ham's medium and assessed for sperm motility and plasma membrane integrity. Although glycerol and Me2SO had no influence (P>0.05), NaCl and sucrose solutions affected sperm motility (P<0.05), but not membrane integrity. Motility of sperm exposed to <600mOsm NaCl or sucrose was less (P<0.05) than fresh ejaculate, but comparable (P>0.05) to the control. As osmolality of the NaCl solution increased, motility decreased to <5%. In a separate study, ejaculates were diluted in Test Yolk Buffer containing 1M glycerol or Me2SO and cooled from 5°C to -120°C at -57.8°C, -124.2°C or -67.0°C/min, frozen in LN2, thawed in a water bath for 30s at 37°C or 10s at 50°C, and then assessed for motility, plasma- and acrosomal membrane integrity. Cryopreservation markedly (P<0.05) reduced sperm motility by 70% compared to fresh samples. Higher (P<0.05) post-thaw motility (20.0±1.9% versus 13.5±2.1%) and membrane integrity (51.2±1.7% versus 41.5±2.2%) were observed in samples cryopreserved in Me2SO than in glycerol. Cooling rates influenced survival of sperm cryopreserved in glycerol with -57.8°C/min being advantageous (P<0.05). The findings demonstrate that although maned wolf spermatozoa are similar to domestic dog sperm in their sensitivity to osmotic-induced motility damage, the plasma membranes tolerate dehydration, and the cells respond favorably to Me2SO as a cryoprotectant.

Induction of ovarian activity and ovulation in an induced ovulator, the maned wolf (Chrysocyon brachyurus), using GnRH agonist and recombinant LH

Assisted reproductive techniques, such as ovarian manipulation and artificial insemination, are useful for enhancing genetic management of threatened wildlife maintained ex situ. In this study, we used noninvasive fecal hormone monitoring to investigate (1) the influence of pairing with a male on endocrine responses of female maned wolves (Chrysocyon brachyurus) to a GnRH agonist (deslorelin) and (2) the efficiency of recombinant LH (reLH) on ovulation induction in females housed alone. Deslorelin (2.1 mg Ovuplant) was given to females that were either paired with a male (n = 4) or housed alone (n = 7); the implant was removed 7 to 11 days postimplantation. Three of seven singleton females were injected with reLH (0.0375 mg) on the day of implant removal, whereas the remaining females (n = 4) did not receive the additional treatment. Fecal samples were collected 5 to 7 days/wk from all females starting 11 days prior to hormone insertion until at least 70 days post implant removal for a total of 11 hormone treatment cycles. Fecal estrogen and progestagen metabolites were extracted and analyzed by enzyme immunoassay. Evidence of ovulation, demonstrated by a surge of estrogen followed by a significant rise in progestagen, occurred in all paired females. Three of the four singleton females that did not receive reLH treatment exhibited no rise in progestagen after an estrogen surge. All singleton females treated with reLH exhibited a rise in fecal progestagen after injection, indicating ovulation. In conclusion, deslorelin is effective at inducing ovarian activity and ovulation in paired female maned wolves; however, exogenous reLH is needed to induce ovulation in females housed alone. The findings obtained from this study serve as a foundation for future application of artificial insemination to enhance genetic management of this threatened species ex situ.