Infectious Enterohepatitis Research Articles

Intracloacally passaged low-virulent Histomonas meleagridis protects turkeys from histomonosis

Histomonosis (blackhead disease or infectious enterohepatitis) caused by the extracellular protozoon parasite Histomonas meleagridis is an important disease of turkeys and a threat to the poultry industry. Due to recent legislation on drug restrictions, research to find new alternatives is an urgent matter in the battle against histomonosis. In the present study, intracloacal inoculation of a low-virulent H. meleagridis strain isolated after serial passages in turkeys clearly demonstrated a reduction of virulence and hence its effectiveness as a vaccine against histomonosis. The low-virulent isolate has been evaluated in a comparative experimental infection study. No mortality nor predominant caecal or liver lesions could be observed in the groups inoculated with 103, 104 or 105 histomonads per bird. Only dilated caeca with a yellow and foamy content could be noticed. Groups inoculated with similar doses of a virulent strain displayed a dose-related pathology and mortality up to 100%. The protective capacity of the strain with reduced virulence could be demonstrated as none of the birds cloacally inoculated with 103, 104 or 105 histomonads died upon challenge with 105H. meleagridis of the virulent strain. Hereby, 71% of the challenge control group died. Interestingly, no or only very minor pathological lesions in the caeca and liver could be detected after challenge of the birds inoculated with the passaged histomonads. In conclusion, cloacal inoculation of the low-virulent strain obtained after serial backpassages was able to induce protection of turkeys against challenge with a virulent H. meleagridis strain.

Non-curative, but prophylactic effects of paromomycin in Histomonas meleagridis-infected turkeys and its effect on performance in non-infected turkeys

Histomonosis (blackhead or infectious enterohepatitis) is a disease of gallinaceous birds, especially of turkeys, and is caused by the protozoan Histomonas meleagridis. Since the ban of all chemoprophylactic and chemotherapeutic products against this disease in the European Union, this parasite causes a considerable amount of economical problems in the poultry industry. Research which could ultimately lead to the discovery of new drugs against this disease is thus highly necessary. Hence, in this study, the efficacy of paromomycin against histomonosis in turkeys was investigated. First, the prophylactic and therapeutic efficacy of this drug against H. meleagridis and its effect on the weight gain of turkeys was determined. Adding paromomycin to the feed (400 ppm as well as 200 ppm paromomycin) or to the drinking water (420 mg paromomycin per liter water, added prior to or on the day of challenge) significantly lowered the mortality rate and the caecal and liver lesion scores after an intracloacal infection compared to infected untreated birds. However, when paromomycin was administered to turkeys in the drinking water after the challenge, no significant differences in mortality or in lesion scores could be observed compared to the infected untreated control group. This demonstrates that paromomycin exerts a purely preventive action against histomonosis in turkeys. Additionally, the weight gain of the treated birds was positively influenced by the use of the drug, as the average weight gain of all treated groups (except for the group treated at the day of first mortality) was significantly higher than that of the untreated control group. Finally, the target site of paromomycin was detected in the SS rRNA gene of H. meleagridis. Consequently, the susceptibility to paromomycin can be correlated to the presence of the binding site of the drug at the 3′ end of the small subunit rRNA gene of the parasite. In conclusion, paromomycin can be used as a new prophylactic measure in the control of histomonosis in turkeys.

Efficacy of a herbal product against Histomonas meleagridis after experimental infection of turkey poults

Histomoniasis (infectious enterohepatitis, blackhead) is caused by the protozoan parasite Histomonas meleagridis (H. meleagridis). After the ban of all prophylactic and therapeutic drugs in the European Union, histomoniasis is increasingly responsible for considerable economic problems to the poultry industry. The aim of this study was to investigate the effect of a herbal product with extracts from cinnamon, garlic, lemon, and rosemary on H. meleagridis in turkey poults in vivo. For this purpose, 60 two-week-old poults were divided into three groups. Group 1 received the herbal product in the feed six days before infection and in water three days before infection, then in feed and drinking water until the end of the experiment. Groups 2 and 3 were left untreated. At week 3 of age, Groups 1 and 2 were infected intracloacally with H. meleagridis. Three weeks after infection the surviving birds were euthanized and examined for pathological lesions. Mortality was 20% in Group 1 and 50% in Group 2. There were no deaths in Group 3. DNA of histomonads was detected in all examined caeca and livers of the dead birds, but was not detected in any examined organ of the surviving birds of all groups. There was no noticeable difference in the lesion scores of the dead birds between the groups. The surviving birds of all groups did not show lesions post mortem. Since all effective prophylactic and therapeutic drugs against histomoniasis were banned in the EU, under given conditions the investigated herbal product seems to be an effective alternative for the reduction of mortality in turkeys caused by histomoniasis.

Evaluation of Dietary Natustat™ for Control of Histomonas meleagridis in Male Turkeys on Infected Litter

Histomoniasis (histomonosis, infectious enterohepatitis, or blackhead) is a disease of turkeys on litter or range caused by the protozoan Histomonas meleagridis, a parasite of worms, primarily spread in feces, in Heterakis gallinarum (cecal worm) eggs, or in Eisenia foetida (earthworms). In this trial, Natustat (Alltech, Inc., Nicholasville, KY), a proprietary plant-derived product, was used at 1.925 kg/tonne and compared with nitarsone in male hybrid turkey diets to 42 days of age on histomonad infected litter (day 7) from broiler breeders. Infected nonsupplemented and uninfected nonsupplemented control groups were also included. Natustat and nitarsone significantly improved 28- and 42-day feed conversion ratios and lowered 28- and 35-day cecal and liver lesion scores compared with infected nonsupplemented turkeys. The body weight at 42 days was greater in the Natustat and nitarsone supplemented groups than in the infected nonsupplemented group.

Histomoniasis in gnotobiotic chickens and turkeys: Biological aspects of the role of bacteria in the etiology

The bacterial requirements for producing infectious enterohepatitis in bacteria-free chickens were different from those for the disease in bacteria-free turkeys. When both Escherichia coli and Clostridium perfringens were introduced with Histomonas meleagridis, mild atypical cecal lesions were produced in 3 of 28 chickens while typical liver and cecal lesions were both present in all of 25 turkeys. When single species of bacterial agents were used, the rate of infection was less. More lesions were produced with C. perfringens than with E. coli. The cecal bacterial flora of conventional chickens, when introduced into bacteria-free chickens, fulfilled the requirement of H. meleagridis for induction of infectious enterohepatitis. Attempts to define the specific bacteria involved in the etiology of the disease in chickens from among 48 different bacterial isolates and Candida albicans were unsuccessful, although very mild disease was produced inconsistently with various combinations of strains of E. coli with Pseudomonas aeruginosa and Streptococcus faecalis or with C. perfringens. Eimeria adenoides, a cecal coccidium, survived when introduced with Histomonos-infected Heterakis eggs into bacteria-free turkeys and supported the growth of some histomonads but not Heterakis gallinarium larvae. Eimeria adenoides did not simulate the role of bacteria in producing infectious enterohepatitis. Disease was produced and Heterakis larvae did survive in conventional turkeys receiving E. adenoides and infected Heterakis eggs. The essential contributing factor of bacteria in the pathogenesis of infectious enterohepatitis was determined to be neither a favorable pH nor an oxidation-reduction potential value within the intestine of the host. The oxidation-reduction potential of bacteria-free cecal contents was strongly positive, that of the conventional chicken with its indigenous microflora was strongly negative, while the potential of the contents of ceca with infectious enterohepatitis was intermediate. The pH of the bacteria-free cecum closely approximates that of the parasite-infected intestine, while the pH of the uninfected conventional cecum was somewhat lower. In the pathogenesis of infectious enterohepatitis, the role of bacteria apparently was more vital for the survival of Heterakis than Histomonas.

Observations Concerning the Use of 1-Methyl-2-Carbamoyloxymethyl-5-Nitroimidazole Against Experimentally Induced Histomoniasis in Turkey Poults

THE activity of 1-methy-2-carbamoyloxymethyl-5-Nitroimidazole** as a prophylactic and therapeutic drug for treating histomoniasis has been reported by Peterson (1967), Whitmore et al. (1967) and Peterson (1968). This report deals with prophylactic use of the drug to a very limited extent. The major aspect of the study involved therapeutic trials whereby Dimetridazole*** was used as a reference standard.MATERIALS AND METHODSNature and Preparation of Infectious Material: Liver and cecal tissues were harvested from poults with distinct lesions of infectious enterohepatitis. Diseased tissues were sliced into small pieces, weighed and combined with physiological saline at the ratio of .5 gm. of tissue/5 cc. saline. The tissues were blended into suspension by the use of a Servall Omni-Mixer. Five cubic centimeters of the tissue suspension was used as a standard inoculum per poult. Approximately one-half of the material was administered per orum directly into the ventriculus and the other half was given…

The Influence of Several Histomoniastats on Performance of Large White Turkeys

HISTOMONIASIS (blackhead disease or infectious enterohepatitis) continues to be one of the major disease problems in turkey production. The prevention and treatment of blackhead disease is obviously of great economic importance to the turkey industry and various drugs have been developed for this purpose. It is desirable that these compounds themselves do not impair performance, especially when administered continuously at prophylactic levels.DeVolt and Holst (1948, 1949) studied the effect of chlorohydroxyquinoline and iodochloroxyquinoline of histomoniasis in turkeys. While these drugs prevented the occurrence of the disease, they depressed growth rate because of decreased food intake. Several reports have indicated that 2-amino-5-nitrothiazole (Enheptin-T) would prevent the occurrence of histomoniasis when fed at 0.05% of the diet, but feed consumption and growth rate were decreased (Jungherr and Winn, 1950; Seeger et al., 1950; McGregor, 1951 a, b; DeVolt et al, 1954; Grumbles et al, 1952 a, b).McGuire and Morehouse (1952)…

Liver Regeneration in Blackhead-Infected Turkeys Treated with 1,2-Dimethyl-5-Nitroimidazole

Histomoniasis (infectious enterohepatitis), a disease which primarily affects the ceca and liver of turkeys, chickens, pheasants and certain other avian species, is commonly called blackhead. The causative agent is a protozoan parasite known as Histomonas meleagridis (Smith, 1895) Tyzzer, 1920. These protozoan parasites first invade the cecal wall, and are then carried through the portal vein to the liver, where they cause extensive destruction. This investigation was made to study and describe the gross pathology and histopathology of the liver of blackhead-infected turkeys before and after medication with 1,2-dimethyl-5-nitroimidazole (dimetridazole).

Studies on the Etiology of Blackhead Disease: The Roles of Histomonas meleagridis and Candida albicans in the United States

INTRODUCTIONALTHOUGH it has been 73 years since Cushman (1893) first described blackhead disease of turkeys (also known by the more descriptive “infectious enterohepatitis”), there is still sharp disagreement as to the etiological agent responsible for production of the disease. Smith (1895, 1910) found a protozoan, Amoeba meleagridis (now known as Histomonas meleagridis Tyzzer, 1920) to be present in diseased ceca and livers. He reported that this protozoan was the apparent causative agent. Cole and Hadley (1908) and Cole et al. (1910) reported that coccidia were the etiologic agents of the disease, but later abandoned this theory (Hadley, 1916a). Jowett (1911) and Hadley (1916a, b) stated that trichomonads were in fact the true disease agents. Allen (1936) and Walker (1948) have stated that a Pentatrichtomonas species, probably actually Trichomonas gallinarum (Allen, 1940), was a causative agent. However, Kemp and Reid (1965) concluded, on the basis of egg production and weight …

Histomonas meleagridis and several bacteria as agents of infectious enterohepatitis in gnotobiotic turkeys

A dual etiology, involving a protozoan ( Histomonas meleagridis) and a single species of bacteria ( Escherichia coli, Clostridium perfringens, or Bacillus subtilis), has been demonstrated for infectious enterohepatitis, using gnotobiotic (“bacteria-free”) turkeys. Koch's postulates for suspected disease organisms have been applied to the combination of H. meleagridis and E. coli and each of the four postulates was fulfilled, indicating that this combination of organisms represented a true etiological pattern for infectious enterohepatitis of turkeys. Negative results for disease production were obained with H. meleagridis alone; H. meleagridis and Aerobacter cloacae + Streptococcus fecalis; or H. meleagridis and Proteus mirabilis, as inocula for gnotobiotic turkeys. Similarly, negative results were obtained from the administration of killed or filtered E. coli + viable H. meleagridis.

Staining Techniques for Differential Diagnosis of Histomoniasis and Mycosis in Domestic Poultry

In the United States the protozoan Histomonas meleagridis has been generally accepted as the etiological agent causing infectious enterohepatitis (= blackhead) of poultry. Presumptive diagnosis on the basis of gross lesions may be inaccurate, since confusion with mycosis infections has occurred. For example, Wiley (9) described a condition which he called pseudoblackhead from which fungal organisms were isolated. Several European workers (2,4,7) have never accepted H. meleagridis as the etiolbgical agent of infectious enterohepatitis but have attributed the disease to infection with yeast-like fungi. The histopathology of histomoniasis and mycoses in chickens and turkeys has recently been studied to clarify the question of the etiology of infectious enterohepatitis (3). The preferred method of identification of H. meleagridis involved demonstration by means of a stage incubator and phase-contrast microscopy. If this attempt is unsuccessful, a reliable differential staining technique is needed. Since neither fungal nor histomonad organisms have a strong affinity for the conventional hematoxylin and eosin as used on tissue sections, other staining techniques are required. Four methods with differential dyes are compared in the present study. Use of one or more of these methods may be helpful in providing a more accurate diagnosis of histomoniasis or mycosis.

Chemotherapy of Histomoniasis of Turkeys I. The Value of 1:2-Dimethyl-5-Nitroimidazole in Prevention and Treatment

In spite of the best known sanitation practices, losses from histomoniasis (infectious enterohepatitis, blackhead) in commercial turkey flocks are sometimes disastrous and often necessitate the use of drugs for prophylaxis or treatment. Drugs for treatment and prevention have been evaluated extensively by numerous investigators, but not many have shown relatively high levels of efficacy in controlling the disease (1,2,3,5,6,9). Among the most effective and widely used chemotherapeutic agents are 2-acetylamino-5-nitrothiazole (Enheptin-A, American Cyanamid Co.) and 2-amino-5nitrothiazole (Enheptin-T, American Cyanamid Co.). Because these are reported to retard maturation of the testes in cockerels (4,8), some flock owners are reluctant to use them to control histomoniasis in replacement breeder flocks during the latter stages of growth. Several of the compounds used to control histomoniasis contain arsenicals. The concern over the use of arsenicals in the rations of animals to be used for human consumption indicates a need for additional remedies which do not contain such chemicals.

The Effect of Dimetridazole on Growth and the Prevention of Histomonosis in Poultry

HISTOMONOSIS (blackhead or infectious enterohepatitis) is produced by the protozoan Histomonas meleagridis and may be transmitted directly from sick or carrier birds, but more often utilizes the embryonated ova of the cecal worm, Heterakis gallinarum, as a vector for indirect transmission. Mortality is the chief cause of economic loss in turkeys, which are extremely susceptible to this infection. Chickens, generally considered to be resistant, become infected under various conditions of management and physiological stress. Loss in body weight and efficiency are substantial in chickens and turkeys because of the relatively ineffective methods of blackhead therapy which are utilized today.Dimetridazole (l,2-dimethyl-5-nitroimidazole) is presently used in Canada and England for prevention and treatment of histomonosis in poultry. An evaluation of the efficacy of this drug has been published in considerable detail (Lucas, 1961Lucas, 1962Lucas, 1963a). The stimulating effect of dimetridazole on the growth of turkeys was reported by Condren et al.…

Studies on the Effect of 1,2-Dimethyl-5-Nitroimidazole on Growth and Reproduction in Turkeys and Its Residual Concentration in Tissue

Abstract THE infectious disease originating in the ceca of poultry, and caused by the protozoal flagellate Histomonas meleagridis is known by various names: histomoniasis, infectious enterohepatitis, and blackhead. It is described as being a subacute or chronic infectious disease with the principal lesions confined to the ceca and liver and is primarily a disease of turkeys. According to Barger et al. (1958) it is one of the most destructive infectious diseases to which turkeys are susceptible and is responsible for large losses in the turkey industry. Grumbles et al. (1952a) investigated the use of Enheptin-P for the prevention and treatment of histomoniasis, and its effect on egg production, fertility and hatchability of turkey eggs. These workers found that continuous feeding of this drug was effective in preventing mortality from blackhead, but it appeared to have little value when medication was started after the disease had appeared in the flock. The 0.1%…

The Effects of 2-Amino, 5-Nitrothiazole on Testis Function in the Turkey

ABSTRACT ONE of the most successful drugs for the treatment and prevention of infectious enterohepatitis in turkeys has been 2-amino, 5-nitrothiazole (Waletsky et al., 1949; Jungherr and Winn, 1950; Grumbles et al., 1952a; and others). Very little is known concerning the effects of this drug on reproduction in the turkey, although it has been shown to seriously impair gonad function in the fowl (Hudson and Pino, 1952; Pino and Hudson, 1953). That this effect of 2-amino, 5-nitrothiazole may be somewhat species-specific is indicated by its failure to affect adversely testis function in the rat (Pino et al., 1954; Shellabarger and Schatzlein, 1955). The turkey also appears to be affected less by this drug than the fowl (Grumbles et al., 1952b). These investigators fed grown turkeys 2-amino, 5-nitrothiazole at levels of 0.03,0.05 and 0.10 percent for 18 weeks. An examination of their data suggests that the 0.10 percent level reduced egg numbers, . . .

The Effect of Furazolidone and Other Drugs on the Growth of Chicks Raised on Old Litter Containing Coccidia ,

AS NEW drugs which show promise as being effective in enhancing the production of poultry are developed, it is desirable to test such drugs under a wide variety of conditions and in comparison with already accepted drugs. With the recent availability of furazolidone, such a test was warranted. While this drug was offered for the control of some Salmonella infections and infectious enterohepatitis, there was some indication that it might be effective for the control of coccidiosis. It was with primary reference to this latter disease that the tests herein reported were conducted. EXPERIMENTALThree experiments have been conducted in which various coccidiostatic drugs have been tested to determine their efficacy in improving the growth rate of fryer chicks maintained on previously used, built-up litter. The litter in the house was originally new wood shavings. The first of 3 experiments was conducted after the litter had been used to raise …

Nithiazide. II. Effect on enterohepatitis in Turkeys.

Summary1. The data presented show that nithiazide [1-ethyl-3-(5-nitro-2-thi-azolyl) urea | was more potent and less toxic than 2-amino-5-nitrothiazole when fed to turkeys with enterohepatitis. 2. Nithiazide was most effective when administered prior to infection or beginning 3 to 7 days after infection. It prevented mortality from enterohepatitis produced either by oral exposure to cecal worm eggs or by rectal inoculation of Histomonas meleagridis cultures. Nithiazide may be administered in the feed or water and is equally effective in either form. 3. The therapeutic feeding of rations containing 0.05% nithiazide, starting 3 days after infection, prevented mortality from infectious enterohepatitis which was lethal for 73% to 83% of the untreated control turkeys.

An Investigation to Determine Whether Immunity to Infectious Enterohepatitis (Blackhead) of Turkeys Develops during Enheptin Treatment

ENHEPTIN (2-amino, 5-nitrothiazole) has been rather widely used in the control of infectious enterohepatitis since the discovery of the drug by Waletzky et al. (1950). The preventive action of the drug also has been confirmed experimentally by McGregor (1949), Jungherr and Winn (1950), and DeVolt et al. (1951). McGregor (1953) suggested the possible beneficial effect of lower (0.035 percent) concentrations of the drug against conditions of moderate exposure to disease. A fluid form of enheptin in various concentrations was found less effective than the powdered form offered in feed. Grumbles et al. (1952a) reported enheptin to be of little value in overcoming the disease when treatment was started after a disease outbreak, but found this drug, as well as 2-acetylaminonitrothiazole (1952b), to be effective in preventing blackhead when medication was started at the time of exposure.Several investigators including Waletzky et al. (1950) and Jungherr and Winn (1950) have noted …

Studies on the Pathogenesis of Infectious Enterohepatitis (Blackhead) of Turkeys

INTRODUCTIONTHEOBALD SMITH (1895) found in livers of turkeys affected with blackhead, a protozoan organism which he called “amoeba meleagridis.” Further description and reclassification of the organism by E. E. Tyzzer (1919) as Histomonas meleagridis established the etiology of the disease. Conflicting views, however, regarding the nature of the causative parasite have been expressed by several investigators.While H. meleagridis has been accepted generally as the causative agent of infectious enterohepatitis, other organisms frequently have been found associated with it in blackhead liver lesions. The presence of such organisms, including both bacteria and protozoa, has tended to perpetuate uncertainties concerning pathogenesis of the disease. With regard to sometime associated protozoa, one of us (H.M.D.) on various occasions over a period of years has found in blackhead livers with histomonads such other protozoan species as Chilomastix, Entamoeba, and Pentatrichomonas gallinarum (DeVolt and Davis, 1936). In addition, blastocystis has been found on …

Physiological Disturbance of the Reproductive System in White Leghorn Cockerels Following the Feeding of Enheptin

THE efficacy of Enheptin (2-amino, 5-nitrothiazole) in the treatment and prevention of blackhead (infectious enterohepatitis) of turkeys has been demonstrated by DeVolt et al. (1951), Jungherr and Winn (1950), and Waletzky et al. (1950), and others. These investigators reported that, except for a short period of retardation in growth due to depressed feed consumption, no toxic effects were noted.At one time blackhead in chickens was considered to be a benign disease and of no economic importance. After vaccination against fowl pox became a common practice, however, a change was noted. It was observed that, though a flock appeared to be in good health at the time of vaccination, heavy losses were suffered from blackhead. These losses usually began ten days to two weeks after vaccination and continued for ten or more days. This sequence of events can be explained by assuming that the chickens were carriers of the blackhead .