Lepromatous placentitis and intrauterine fetal infection in lepromatous nine-banded armadillos (Dasypus novemcinctus)

Three pregnant lepromatous armadillos along with the three sets of four fetuses and their placentae were studied histopathologically. Mycobacterium leprae were present in the decidual tissue, trophoblastic cells which line the chorionic villi, and in the cells that form the internal structure of the villi. Acid-fast organisms were also seen in the spleens of three fetuses. Congenital infection is clearly possible in leprosy in the armadillo and may also occur in humans.

Comparability among histopathologists in the diagnosis and classification of lesions suspected of leprosy in Malawi

Identical slides from 200 biopsies obtained from individuals suspected of having leprosy during the course of an epidemiological survey in Northern Malawi were examined sequentially and independently by three histopathologists, using a standard protocol to report their findings. Their results are compared among themselves and with a standardized clinical assessment of each subject. There was more agreement among the histopathologists as to classification of leprosy cases than there was on the diagnosis of leprosy. The proportion of biopsies considered to show definite evidence of leprosy varied from 39% to 58% among the histopathologists. An appreciable additional proportion of biopsies (11.5% to 38.5% for the three histopathologists) was considered to show evidence suggestive but not pathognomonic of leprosy. Although there was, in general, good agreement on classification, the proportion of biopsies considered to show evidence of indeterminate leprosy varied from 1.5% to 21.5% among the three histopathologists. This suggests that some of the reported differences in the prevalence and proportion of indeterminate leprosy in different populations is due to terminology alone. A follow-up meeting of the study participants revealed that many of the differences in diagnosis certainty were due to difficulties in interpreting evidence of nerve involvement. It is recommended that greater attention be paid to the difficulties of diagnosing leprosy on histopathological as well as clinical grounds. A revised standard protocol for reporting histopathological evidence of leprosy is presented.

Thorns in armadillo ears and noses and their role in the transmission of leprosy

Both ears from 494 wild nine-banded armadillos (Dasypus novemcinctus) and nose specimens from 224 animals were collected and histopathologically studied. Lepromatous granulomas were present in the ear specimens of ten of 494 animals. There were thorns in the ears of 22.5% of animals, and in 36.6% of the nose specimens. In one armadillo, there was evidence to suggest that Mycobacterium leprae entered the tissue through the thorn pricks. In the normal habitat of the armadillo in Louisiana there are thorny bushes consisting mostly of the green briar and the southern dewberry. Thorn pricks as a means of transmission of leprosy in the wild armadillos is suggested.

A random survey of leprosy in wild nine-banded armadillos in Louisiana

On the basis of the finding that lepromatous granulomas were almost always seen in the ears of armadillos with disseminated leprosy, a random survey of the prevalence of the disease among wild armadillos in the state of Louisiana, U.S.A., was conducted by examining histopathologically both ears of armadillos killed on the roads by automobiles. Ten (2%) of the 494 animals examined had disseminated leprosy. If a killed lepromatous armadillo releases up to 10 Mycobacterium leprae into the environment, the importance of the event to the epidemiology of leprosy must be considered.

Local and systemic effects of intradermal recombinant interferon-gamma in patients with lepromatous leprosy

Evidence that interferon-gamma may be a physiologic macrophage-activating factor, and that macrophage activation may be defective in lepromatous leprosy, led us to test the effects of intradermal injection of low doses of recombinant interferon-gamma in six patients with this disease. Interferon-gamma, 1 or 10 micrograms, was administered daily by jet gun for three days into a single cutaneous lesion. A biopsy specimen was taken from the injection site on the sixth study day and compared with specimens obtained previously from a site where no injection had been made or where excipient alone had been injected in the same way as the interferon. Interferon-gamma elicited local effects similar to certain features of delayed-type hypersensitivity reactions or tuberculoid leprosy, including induration, T-cell and monocyte infiltration, keratinocyte proliferation, diminution of epidermal Langerhans cells, and dermal and epidermal cell HLA-DR (Ia) antigen expression. At some of the sites of interferon-gamma injection, there was also an apparent decrease in acid-fast bacilli. Before treatment, monocytes from patients with lepromatous leprosy released 48 percent as much hydrogen peroxide as did monocytes from controls in response to phorbol myristate acetate, and 36 percent as much as those from controls in response to Mycobacterium leprae. When recombinant interferon-gamma was injected, these responses became normal. No toxic effects were observed. These observations suggest that interferon-gamma can mediate certain manifestations of delayed-type hypersensitivity or cell-mediated immunity in vivo, and that recombinant interferon-gamma should be tested for possible therapeutic effects in certain nonviral infectious diseases.

A single skin lesion--an unusual presentation of lepromatous leprosy

Lepromatous leprosy presenting as a solitary lesion with a high bacterial count is a rare occurrence. Such a case has been followed at the National Hansen's Disease Center, Carville, Louisiana, U.S.A., since 1977. The lesion was located on the left elbow and had been present for about nine months. The bacterial index in the lesion was 5+ and the morphological index was 0%, but slit-skin smears elsewhere were negative. The histopathology of the lesion was that of subpolar lepromatous leprosy, and the lepromin skin test was negative. Growth of the organism in the mouse foot pad was characteristic of Mycobacterium leprae, and the patient's response to dapsone monotherapy has been excellent. Therefore, this patient with a single skin lesion has lepromatous leprosy histologically, immunologically, and bacteriologically. This case illustrates the importance of slit-skin scrapings and biopsy in new cases with unusual lesions and, secondly, suggests that there are factors yet undetermined which play a significant role in determining host response to M. leprae.

Transmission of leprosy in nude mice

Nude mice in groups of 10 were exposed to M. leprae by subcutaneous injection and topically through the nose, lungs, mouth, stomach and skin, broken and unbroken. Animals injected subcutaneously and those topically exposed to M. leprae through the nose developed localized disease which in the course of time became generalized. The nose seems to be the site of entry of M. leprae in this model. To the extent that these results can be generalized to humans exposed to M. leprae, it would seem that leprosy bacilli impact topically on the nasal mucosa or are inoculated subcutaneously.

Effect of repeated lepromin testing on experimental nine-banded armadillo leprosy

Twenty-eight armadillos were lepromin tested and infected with M. leprae; 18 intravenously and 10 intradermally. The lepromin test was repeated after 3 months and at intervals of 6 months thereafter until their death or sacrifice up to 30 months. The one animal with tuberculoid lepromin was resistant and 14 of the 16 with lepromatous lepromin developed generalized disease. Of the 11 with borderline lepromin, 6 developed disseminated disease and 5 were resistant. There is a definite relationship between resistance and tuberculoid lepromin in the armadillo. Repeated lepromin testing had no effect in the rate of infection and the course of the disease in animals infected intravenously. In the intradermally infected animals the results were inconclusive. Whereas all the 20 animals with disseminated disease showed lesions in the liver, spleen and lymph nodes, only 4 animals had sciatic nerve involvement. Peripheral nerve trunk is not necessarily the preferred site in the armadillo. Lung lesions were an important cause of death in lepromatous armadillos.

First lesion in experimental armadillo leprosy

Eighteen armadillos were infected intravenously with 10(8) M. leprae and 10 intracutaneously with 10(7) M. leprae. Among those which developed disseminated disease, a nodule at the site of inoculation was the first lesion noticed in 14 of the 16 infected intravenously and 4 of the 4 infected intradermally. It is possible that in human leprosy the first sign of infection is localized proliferation of M. leprae at the site of entry, and even nodule formation in lepromatous patients. It may be important to search for asymptomatic swelling or keloid-like lesions in skin or in nasal mucosa while screening a population for early leprosy.

Manifestations of experimental leprosy in the armadillo

Three experiments, using different routes and doses of infection, were conducted using 42 armadillos. Thirty-six of them developed generalized disease. There is no significant sex or age difference in susceptibility. Route and dose of infection make very little difference in the disease prevalence except that the intravenous administration of a large dose reduces the period of development of generalized disease. It is quite possible that in armadillos the resistance to the disease is partly genetic. Although a majority of the armadillos developed lepromatous disease, borderline leproma is fairly common. In skin nodules large colonies of extracellular bacilli are demonstrated. Bacilli are also demonstrated in liver parenchymal cells.

Attempts to breed the nine-banded armadillo (Dasypus novemcinctus) in captivity--a preliminary report

Three pairs of nine-banded armadillos were successfully kept in wire-fenced pens in natural surroundings with light, temperature, and weather as in the farms of Louisiana, a natural habitat of armadillos. One female delivered quadruplets after being in the experimental pen for 10 months and 11 days. It is possible that in this experiment breeding of nine-banded armadillos in captivity has been achieved under controlled conditions for the first time.

Enzootic schistosomiasis in a Louisiana armadillo

Trematode eggs compatible in characteristics with those of Heterobilharzia americana, a probable cause of human schistosomal dermatitis in the Gulf States of the U.S., were found in the cirrhotic liver and other viscera of a wild-caught armadillo in Louisiana. Although adult worms were not found, the current observation suggests a need to extend the known host range of this common schistosome parasite of carnivores and other wild animals in the South, and may have additional implications in the context of the public health importance of the armadillo.

Early leprosy with perineural proliferation

A 62-year-old woman, who lived in an area of the United States nonendemic for leprosy, was seen for an enlarging anesthetic lesion that involved the entire left breast. Microscopic examination of skin biopsy specimens taken from the edge of the lesion disclosed chronic perineural inflammation and neural proliferation, with an acid-fast bacillus demonstrable in one nerve. Granulomas, giant cells, epithelioid cells, nerve abscesses, or other characteristics of tuberculoid leprosy were not seen. This woman had a skin lesion of leprosy in an atypical site. It appeared to be indeterminate on pathologic examination and was accompanied by an unusual degree of neural proliferation.

Variable lepromin response to Mycobacterium leprae in resistant armadillos

Eight armadillos resistant to the infection of Mycobacterium leprae were lepromin tested. The tissue response was tuberculoid in 5, borderline in 2, and lepromatous in 1, thus showing a wide variation. It is seen that although cell-mediated immunity as evidenced by a tuberculoid granulomatous response to killed M. leprae is associated with resistance to the disease, there may be other yet unknown factors which protect armadillos from the infection. Lepromin responses were recognized histologically even at a low dose of 10(3) organisms, and the response increased with the dose up to 10(7) organisms. The tissue reaction to live organisms was the same as that to killed ones, and autoclaving of M. leprae produced no change in the tissue response to the antigens of M. leprae.

Invasion of liver parenchymal cells by Mycobacterium leprae in an experimentally infected nude mouse. An electron microscopic study

Liver tissue from a nude mouse infected with Mycobacterium leprae for 18 months was examined using light and electron microscopes. Numerous microgranulomas composed of macrophages were present throughout the liver. M. leprae in large numbers were present in Kupffer cells, macrophages, endothelial cells, and liver parenchymal cells. The study shows that the lower temperature of about 31 degrees C optimal for the growth of M. leprae is relative rather than absolute, and that M. leprae can invade even liver cells.

Borderline leprosy in an experimentally infected armadillo

Out of six armadillos infected intravenously with 4.66 x 10(8) M. leprae, one developed a delayed hypersensitivity tissue response with the formation of an epithelioid cell granuloma. It is suggested that, although 80% of armadillos are susceptible to infection with M. leprae, some among these susceptible ones will exhibit varying degrees of delayed hypersensitivity reactions. These animals may go through a borderline phase before ultimately undergoing lepromatous degeneration.

Tissue response to lepromin, an index of susceptibility of the armadillo to M. leprae infection--a preliminary report

In this preliminary report the histopathological appearance of the lepromin reaction in armadillos was correlated with their response to infection with M. leprae. Three different types of lepromin response were described, namely the lepromatous, the borderline, and the tuberculoid lepromin reactions. It was found that 10 out of the 11 animals with a lepromatous lepromin reaction and the one animal with a borderline lepromin reaction developed disseminated disease. The two with a tuberculoid lepromin reaction and one of the 11 with a lepromatous lepromin reaction failed to develop leprosy. It is suggested that by using the lepromin response it is possible to assess, to a great extent, the susceptibility of armadillos to infection by M. laprae. The pros and cons of using the armadillo as an animal model for a vaccine trial are briefly discussed.