CHAPTER XXVI
YAWS OR FRAMBOESIA
HISTORY AND GEOGRAPHICAL DISTRIBUTION
=History.=—Some authorities think that a disease described by the Arabian physicians of the 10th century was yaws, but the first description of what was undoubtedly yaws was that of Oviedo, who in the 16th century described such an affection as existing in the West Indies. Bontius, later on, noted the existence of the disease in the East Indies as well as in the West Indies.
It is known that yaws often occurred in epidemic form on board the slave ships and it is thought that this disease may have been an African importation into the new world.
=Geographical Distribution.=—Yaws is essentially a disease of tropical regions.
In Africa it is very prevalent in the equatorial region, especially in the Congo Free State. It is also found more rarely in Tripoli and Algiers and to a less extent in the Sudan region. It is common in the West Indies and tropical America.
In Asia it is very prevalent in the Malay Peninsula, Siam, the East Indian Islands and in the Philippines. It does not exist in Japan. In many of the islands of the Pacific it is exceedingly prevalent,
## particularly in Samoa. It is also present in Northern Australia.
ETIOLOGY AND EPIDEMIOLOGY
=Etiology.=—In view of the fact that many great authorities, especially J. Hutchinson, insisted upon the syphilitic nature of yaws it was a matter of great interest when Castellani, in 1905, discovered the causative organism which is characterized by the same sharp-cut, corkscrew spirals that are noted with the syphilitic spirochaete discovered by Schaudinn in the same year. _Treponema pertenue_ is found in the epidermis of the yaws granuloma and has been demonstrated in lymphatic glands and spleen. Although it has not been demonstrated in the blood, through microscopical examination, it must exist there as monkeys infected with the blood of yaws patients develop the lesions of yaws in which the spirochaetes are present. Another name for the organism is _Spirochaeta pallidula_; this however is only a synonym.
Inoculation experiments as well as clinical manifestations show yaws and syphilis to be distinct. Thus Charlouis, in 1881, inoculated a native suffering from typical yaws wistations of syphilis followed. There have been many instances of the development of yaws, naturally and by inoculation, in those affected with syphilis. Nichols has shown that a rabbit which had been infected intratesticularly with _T. pallidum_ and then cured by salvarsan did not show immunity to _T. pertenue_ when the latter was used to infect the testicle.
In the monkey inoculation over the eyebrow gives a flat dry and scaly lesion with syphilitic material while yaws inoculation gives a softer, more oedematous one.
Levaditi and Nattan Larrier have noted that monkeys which had been inoculated with syphilis were immune to yaws inoculation but yaws monkeys could be infected with syphilis, thus indicating that yaws was a mild form of syphilis. In Guam, it has recently been shown that 68% of cases of gangosa, a disease supposed to be a tertiary form of yaws, give a positive luetin reaction. This would indicate a close relationship between yaws and syphilis.
Salvarsan is more specific for yaws than it is for syphilis and the percentage of positive Wassermann tests is as great in yaws as in syphilis.
Notwithstanding the above points, which would indicate a close relationship, all authorities are now agreed that clinical and pathological evidence show the two diseases to be separate entities.
=Epidemiology.=—Charlouis inoculated 32 Chinese prisoners with scrapings from yaws lesions. The disease developed in 28 of them, first showing itself at the site of inoculation.
Paulet inoculated 14 negroes with yaws material and after a period of incubation of from twelve to twenty days a primary lesion appeared, to be followed by the generalized eruption. In naturally acquired yaws the period of incubation is from three to six weeks. These experiments are in line with the known fact that any skin abrasion which comes in contact with a yaws lesion becomes infected, as when the mother nurses an infant with lesions on its face and develops a yaws lesion at the site of some fissure about the nipple.
Yaws shows a striking limitation to the tropics and in a disease so communicable by direct contact it seems remarkable that it does not spread from the occasional case introduced into temperate regions. In the tropical world it seems limited to low level areas. Another feature of yaws epidemiology is the vastly greater susceptibility of colored races, even those of mixed white blood showing a certain degree of immunity.
All evidence is against a congenital form of yaws.
In particular are flies important factors in the transmission of the disease, transferring the secretions from yaws lesions to abrasions or ulcers on the skin of healthy persons.
The greater the attention to personal hygiene the less probable is the spread of yaws, so that Europeans are rarely infected while the disease may be prevalent in the native population.
In countries where it is prevalent it is chiefly a disease of children, the adults possessing immunity as the result of attacks in childhood.
PATHOLOGY
The primary yaws lesion is histologically the same as the lesions of the generalized eruption of the second stage. In these lesions we fail to find the endothelial proliferations and perivascular round cell infiltrations so characteristic of syphilis. There is great thickening of the interpapillary pegs of the epidermis which dip down deeply into the corium. Areas are noted in the epithelium containing swollen degenerated epithelial cells, polymorphonuclears and granular débris. There is marked oedema in the corium with dilatation of the blood vessels and lymphatics.
There is less oedema of the corium in yaws than in a syphilitic condyloma thus accounting for the greater dryness of the former. The main point in the pathology of a yaws lesion is the predominating involvement of the epidermis and the comparatively slight change in the corium.
In a Levaditi-stained specimen the spirochaetes are found in the epidermal layers instead of in the corium as with syphilis.
The visceral organs and central nervous system are not affected although Harper has reported cases of tabes and general paresis in Fijians following yaws. He excludes syphilis.
SYMPTOMATOLOGY
It is usual to consider the clinical course of yaws as exhibiting two stages, the primary one, which comes on from 2 to 5 weeks after introduction of the virus and is characterized by a papular initial lesion, which later shows the fungoid appearance of a typical yaws tubercle, and the secondary stage in which yaws lesions similar to the initial one develop as a generalized eruption.
Some authorities recognize a tertiary stage in which gumma-like nodules, with subsequent ulceration, appear. There is much evidence to indicate that a destructive ulceration of the nasopharyngeal region, in natives of Guam, is a tertiary manifestation of yaws.
[Illustration: FIG. 121.—Yaws. This case shows an abundance of yaws tubercles on face. Distribution on trunk and extremities less extensive. (From Ruge and zur Verth.)]
_The Primary Stage_.—During a period of incubation, averaging three weeks, vague digestive troubles, nocturnal headache, joint pains and an irregular fever may be noted which often abate upon the appearance of the initial papule at the site of inoculation. There may be enlargement and tenderness of the lymphatic glands about the time of the appearance of the eruption. This initial lesion may be single or there may be several papules grouped together. In some cases it may be impossible to get any history of a primary lesion or it may have been overlooked. The primary lesion is almost invariably extra-genital and it has the same appearance as the lesions of the secondary stage, thus differing from syphilis.
[Illustration: FIG. 122.—Child with yaws. (From U. S. Naval Medical Bulletin.)]
The yaws lesion, whether primary or secondary, starts as a papule which in a few days enlarges to the size of a small pea. It is conical and surrounded by an inflammatory areola. At this time the thickened epidermis begins to crack and a yellowish sero-purulent fluid exudes from the underlying fungoid base. They bleed easily but are not painful. It is this fungoid yellowish or yellowish-red tubercle which has been thought to resemble a raspberry, hence the name framboesia. French authors liken it to a fig which has been turned inside out. The moist or crusting surface soon shows an underlying ulcer, which may dry up leaving a pigmented spot or become exuberant and appear as a mass of fungating granulations, 1 to 2 inches in diameter. Such lesions are given the name “mother yaw.”
_The Secondary Stage_.—In from six weeks to three months after the appearance of the initial lesion, which may have dried up and left only a scar, or which more commonly is still present, there again set in malaise, headache and joint pains with an irregular inconstant fever.
The secondary eruption is made up of lesions having the same character and course as the primary yaws tubercle. In the general eruption, the papules appear frequently in the region of the junction of skin and mucous membrane as about mouth, nose and anus. In such regions they may become very moist and resemble the mucous patches of syphilis.
Besides their location on face and about the perineal region they are numerous on neck, arms, legs, and buttocks. They are rare on the trunk and scalp.
In their ordinary locations the yaws tubercles are not painful unless pressed firmly but when located on the palms of the hands or soles of the feet the thick skin of these regions exerts pressure so that in such situations the lesions are painful.
In this stage yaws does not involve mucous membranes or affect the viscera.
The secondary stage lasts from 3 or 4 months to 2 or 3 years, the yaws tubercles coming out in successive crops in long standing cases.
_The Tertiary Stage_.—Daniels noted in the Fiji Islands destructive lesions of the naso-pharyngeal region which he thought might be associated with a preceding yaws attack. He noted cutaneous lesions which resembled lupus vulgaris. Boissiere has noted not only the nasopharyngeal lesions and lupus-vulgaris-like ones but also tibial involvement, joint swellings and dactylitis.
Numa Rat describes various tertiary manifestations. There may be subcutaneous nodules about ankle or leg which soften and may produce bone lesions and deformities. He notes destructive lesions of nares, pharynx and palate which may set in years after an attack of yaws. His description of the process starting as an ozoena or sore throat followed by destruction of the uvula, velum palati and septum nasi is much like gangosa. Howard has noted the greater frequency of destructive lesions of the nasopharynx in those parts of Africa where yaws is prevalent than in parts where syphilis prevails.
[Illustration: FIG. 123.—Tertiary jaws, “Gomma”. (Johns Hopkins Bull., Moss and Bigelow.)]
According to Castellani the characteristic lesions of tertiary yaws are gummatous nodules and deep ulcerations. Such ulcerations may give rise to contractures.
In Guam the view now prevails that the condition known as gangosa is a form of tertiary yaws.
Other than a moderate anaemia there is very little in the blood of yaws which differs from the normal.
_Peculiar Types of Yaws_.—When yaws tubercles develop in the palms of the hands or soles of the feet we have a very painful and incapacitating condition resulting. The pressure of the thick unyielding epidermis on the tubercles beneath gives rise to marked pain, thus differing from tubercles on other parts of the body. Eventually these tubercles break through and the affected sole may have a worm-eaten appearance. The name “crab yaws” is a common one for such a condition involving the soles of the feet and is so-called from the difficulty in walking which has a resemblance to the locomotion of a crab. In some cases the yaws tubercles adjoin one another to form a circle enclosing unaffected skin. Such an arrangement of lesions is often described under the name of “ringworm yaws.”
[Illustration: FIG. 124.—Tertiary yaws. Clavus or Crab-yaws. (Johns Hopkins Bull., Moss and Bigelow.)]
DIAGNOSIS
=Clinical Diagnosis.=—Bromide eruptions may greatly resemble yaws but the history of the taking of the drug and the effect upon withdrawal should differentiate.
_Syphilis and Yaws._—Degorce gives a very complete table of the points of difference between syphilis and yaws, some of the more important of which are the following:
YAWS
1. Primary lesion of soft consistency, or very little infiltrated, with granulating or pimply surface, situated almost invariably extragenitally, resembling the secondary lesions. Lymphadenitis not marked.
2. Roseola resembling that of syphilis but rarer.
3. Secondary cutaneous lesions at first in the form of conical elevations of a light red color, not infiltrated at base, appearing in close groups. The lesions are similar to those of syphilis, namely, on the scalp in the form of encrusted papules; on thin-skinned regions in the form of ulcerating papules, and in the case of the palm of the hands and plantar surface of the feet, in the form of simple papules.
4. Circinate lesions with the edges more raised than in syphilis, covered with yellow crusts.
5. On the face lesions of the same type, but more striking and with irregular projections.
6. Cutaneous lesions do not itch.
7. Perionychia similar to that of syphilis, but occasionally giving rise to pimply lesions.
8. Alopecia has not been described.
9. Lesions in the buccal and pharyngeal mucosa often absent. No erythema. No typical mucous patches. Sometimes fissures at the angles of the mouth. The typical lesions are raised, pure white and occasionally covered with intact epithelium.
10. Lesions with prominent edges or even pustular with yellowish crusts, occasionally also ulcerations resembling mucous patches.
11. Similar condylomata, but larger and more raised.
SYPHILIS
1. Primary lesion infiltrated and indurated, with flat and smooth surface, ordinarily situated on the genital organs; often accompanied by abundant lymphadenitis. Phagedenic processes frequent.
2. Roseola present.
3. Secondary cutaneous lesions papular from the first, dark red, infiltrated and fairly regularly scattered.
4. Circinate lesions with pink edges, slightly raised, with fine scales.
5. Seborrheic syphilides on the face.
6. Cutaneous lesions do not itch.
7. Perionychia present.
8. In syphilis, alopecia rather the exception.
9. Lesions in the buccal and pharyngeal mucosa are not numerous and are slight in degree. Erythema of the soft palate and pharynx occurs. Mucous patches. Ulcers of the lips and at the angles of the mouth.
10. In the glans, prepuce or vulva, the lesions are more or less typical mucous patches.
11. Moist condylomata at the margin of the anus.
The authorities generally discuss extensively the points of distinction between yaws and syphilis. This is probably more connected with possible relationship than practical importance in diagnosis.
=Laboratory Diagnosis.=—The staining of the juice from yaws tubercles by the India ink method or with Giemsa’s stain is the usual procedure.
Baermann gives the percentage of positive Wassermann reactions in untreated, clinically positive cases, as 80 to 100%; in treated cases, 50%, and in the latent ones as from 35 to 40%. In an examination of the serum of 281 cases of gangosa, Halton obtained 37.3% positive Wassermann reactions. Kerr found that 73.8% of 2,429 natives of Guam had had yaws, usually in childhood.
Among other diseases which may be confused with yaws, particularly as regards the nasopharyngeal ulcerations of tertiary yaws, may be mentioned American cutaneous leishmaniasis. The differentiation rests in finding _Leishmania tropica_ in such lesions.
Sections from a yaws tubercle treated and sectioned according to Levaditi’s method show the treponemata in the region of the thickened interpapillary pegs of the epidermis.
PROGNOSIS
This is almost entirely favorable as regards danger to life. The death rate is approximately ½ of 1% and such fatalities generally occur in young children in whom secondary infections develop on the site of the ulcerating yaws lesions.
PROPHYLAXIS AND TREATMENT
=Prophylaxis.=—Daniels thinks the frequency of infection about the angles of the mouth, which frequently show fissures, is explained by the exchange of particles of food or other substances by children, thus transferring the infection.
Of course care should be taken to prevent articles of clothing contaminated with yaws discharges from acting as infecting agents.
The main point in prophylaxis is to prevent flies from having access to abrasions on the skin, so that all cuts or sores should be protected by dressings. The sound skin is a barrier to infection.
=Treatment.=—It can certainly be stated that in salvarsan we have an absolute specific for yaws, the results which obtain in a few days being almost miraculous when one considers the protracted normal course of the disease.
The drug is given intravenously although neosalvarsan intramuscularly is more convenient for those not prepared to give intravenous injections.
The methods of administration are exactly as for the treatment of syphilis. The drug gives best results when used early in the course of the disease.
Doses of 0.4 gram of salvarsan usually suffice and frequently one dose effects a cure. The dose for women, children and thin individuals should be less than for strong adult men. Atoxyl does not seem to be effective in yaws. In other words the methods of treatment are the same for the two treponemata, except that the effect of salvarsan may be termed specific for yaws and less so for syphilis. Bergen found that about 4% of cases treated with salvarsan or neosalvarsan relapsed. The average time to effect a cure was eleven days.
Many of the older writers have reported the value of mercury in the treatment of yaws but the present view is that this drug has very little if any place in the therapy of the disease. Potassium iodide does seem to be a very useful drug in the absence of opportunity for obtaining some arsphenamine product. Where the specific remedy cannot be secured the next best treatment is Castellani’s yaws mixture. The formula for the preparation is the following:
Tartar emetic one grain (0.06 gm.) Potassium iodide twenty grains (1.3 gms.) Sodium salicylate ten grains (0.6 gm.) Sodium bicarbonate fifteen grains (1 gm.) Chloroform water and syrup one ounce (30 cc.)
The above is a single dose and it is given well diluted about three times daily. This treatment is continued for about a week and after an interval of another week is resumed according to the response to such treatment. In children between seven and fifteen years the dose is reduced one-half and for younger children correspondingly. It would seem well to start treatment with a smaller dosage than the standard one, being guided by the ability of the patient to stand an increase in the dose of the drugs.
For local treatment use antiseptic dusting powders as iodoform or boric acid.
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