TRANSACTIONS OF THE ROYAL SOCIETY OF TROPICAL MEDICINE AND HYGIENE (1996) 90,241-243 241

Bartonellosis in Zamora Chinchipe province in Ecuador

Philip Cooper’>*, Ronald Guderian’, Wilson Paredesl, Robert Danielsl, Divi Pereral, Mauricio Espinell, Macias Valdez3 and George Griffin ’ lDepartment of Clinical Investigations, Hospital Vozandes, Quito, Ecuador; 2Division of Infectious Diseases, St George’s Hospital Medical School, Tooting, London, UK; 3Hospital Cantonal de Zumba, Zumba, Ecuador

Abstract Human bartonellosis was investigated in the Ecuadorian province of Zamora Chinchipe; 17 cases were identified retrospectively from hospital records over the period 1984-1995, mostly from 6 communities in the provincial district of Zumba. A questionnaire concerning risk factors for disease transmission was ad- ministered in these 6 communities. Blood samples were taken from individuals with current febrile ill- nesses or skin lesions suggestive of bartonellosis. Samples for detection of Bartonella bacilliformis were also taken from all school-age children in communities where historical cases had been identified by question- naire. No bacteriologically positive case was identified and no evidence of asymptomatic infection was de- tected. Risk factors for disease transmission, identified by the questionnaire, included the presence of sick or dying chickens and guinea-pigs. It was suggested that bartonellosis is a zoonosis with wild animals, probably rodents, as the reservoir. The widespread use of residual insecticides and the easy availability of antibiotics is likely to have modified the epidemiology of this disease over the last decade.

Keywords: bartonellosis, Bartonella bacillifork, Ecuador

Introduction Bartonellosis, or Carrion’s disease, is caused by infec-

tion with Bartonella bacilliformis. a Gram-negative vleo- morphic coccobacillus transmitted to huma& by sand- flies of the genus Lutzomyia. The disease is thought to be endemic in inter-Andean valleys in Peru and Ecuador at altitudes of between 1000 and 3000 m (HERRER, 1957).

Infection with B. baciZZ&mk may cause severe and fa- tal clinical disease, particularly in immigrants to an en- demic area (HERRER, 1990). The acute phase, Oroya fe- ver, is manifested by severe anaemia, fever, and musculoskeletal pains which may be complicated by sec- ondary infections, particularly with Salmonella spp. (CUADRA, 1956). Recovery from primary infection is generally followed after 2 to 8 weeks by the appearance of haemangiomatous skin lesions, verruga peruana, which eventually heal without scarring (RICKETTS, 1949). These blood-filled blisters or warts appear in crops in a centrifugal distribution and may persist for months or years! during which time the patient may or may not complam of accompanying fever and rheumatic pains (RICKETTS, 1949). Most inhabitants of endemic communities report verruga peruana in childhood with or without an antecedent flu-like illness.

Little is known of the current epidemiology of bar- tonellosis in Ecuador. The first suspected case reported this century was by Rigail in 1910 (GUEVARA DE VELIZ & OLLAGUE, 1984). Outbreaks of bartonellosis have been reported from Zaruma and Portovelo in El Oro province (L. Alcivar, 1940; unpublished report), Loja in Loja province (MORAL, 1939), and Zumba in Zamora Chinchipe province (ALVARADO COBO, 1942; BERRU CUEVA, 1954; V. Reyes, 1980, unpublished report). Spo- radic cases of human disease have also been reported from several provinces (HEINERT, 1928; OLLAGUE & GUEVARA DE PEREZ, 1976; CARVAJAL et al., 1978; LEON & LEON, 1986).

The objective of this survey was to define the current epidemiology of bartonellosis in Zamora Chinchipe province and to investigate potential vectors and reser- voir hosts.

Materials and Methods Study ptipulation

Communities to investigate were identified by exami- nation of hospital records-(in-patients and out-patients) at the Hosvital Cantonal de Zumba fHCZ) in the vrov- ince of ZaAora Chinchipe in south-wester& Ecuador on the frontier with Peru. Cases of bartonellosis were iden-

Address for correspondence: Dr I?. Cooper, Laboratory of Para- sitic Diseases, National Institutes of Health, Building 4, Room 126, Bethesda, Maryland 20892, USA.

tidied from 6 agricultural communities, El Tablon, El Chorro. La Chonta, Pucanamba. Barra La Cruz. and Chito, situated in a sparsely populated area of low moun- tainous tropical forest at altitudes of 800 to 1750 m.

An active search for verruga peruana was made in these communities either from house to house or by set- ting up a skin clinic after giving adequate notice to the relevant community.

Patient and sample examination Individuals with fever or skin lesions suggestive of

verruga peruana were further examined in the following way: a complete physical examination was made for the presence of other skin lesions; capillary blood samples were taken for thick and thin films and culture.

Sample processing Blood j3n.s and haematocrit measurement. Standard

methods were used for the staining and examination of thick and thin blood films stained with Giemsa’s stain and the measurement of haematocrits. Haemoglobin levels (g/dL) were estimated from haematocrit values.

Cultures. Culture medium (Colombia agar, Difco) was prepared according to the manufacture& instructions and autoclaved: 10% hevarinized whole human blood was added and ihe mediim left to set at a slant in sterile glass culture tubes. Approximately 50 PL of patient’s capillary blood were added to each tube. The cultures were incubated at 28°C and examined weekly for the presence of bacterial colonies.

Questionnaire A questionnaire designed to assess possible risk fac-

tors for disease transmission was administered in Span- ish to the head of each household in the 6 communities. Each head of household was presented with a set of pho- tographs which included verruga peruana and the major differential diagnoses (leishmanial ulcers, molluscum contagiosum, common warts, yaws, chickenpox, and trooical ulcer) and asked if he or anv member of the fam- ily-had sufferkd from any of these l&ions within the last 5 years. A case household was defined as one where at least one person had had the skin lesions of bartonellosis (verruga peruana) in the last 5 years. Information re- quested by the questionnaire included biographical in- formation, type of construction of the house, type of bedding, sources of drinking water, the presence of la- trines, rubbish disposal, electricity, previous spraying with DDT or malathion, animal contact (domestic and wild mammals, and insects), sickness in domestic ani- mals, type of work, visits to the mountains, recent deaths in the family, and symptoms of bartonellosis. Communi- ties where cases of verruga peruana had been identified

PHILIP COOPER ETAL. 242

by questionnaire were revisited and all school-age chil- dren were bled for blood films and culture.

Statistical analysis Proportions were compared using Fisher’s exact test.

Results Seventeen cases of bartonellosis were identified

retrospectively from hospital records at HCZ. The me- dian age of patients was 9 years (range 4-57 years) and 11 (65%) were male. Twelve (71%) presented with acute bartonellosis (fever and anaemia), and 6 (29%) with ver- ruga peruana. One patient who presented with acute bar- tonellosis re-presented subsequently with verruga pe- ruana. Other clinical findings were fever (88%), pallor (59%), musculoskeletal pain (18%), hepatomegaly (18%), generalized lymphadenopathy (IX%), jaundice (12%), and splenomegaly (6%). Of the 13 tested, (46%) had B. bacdZijiwrvzis in blood films. The median haemoglobin level was 7.3 g/dL (range 3.0-12.7 g/dL), and it tended to be lower in patients with acute bartonellosis.

The numbers of households sampled by questionnaire in each community were: Chito, 13 (13125 or 52% of all households); El Chorro, 19 (19/60 or 32%); El Tablon, 18 (18128 or 64%); Pucapamba, 6 (6/10 or 60%); Barra La Cruz, 13 (13/20 or 65%); and La Chonta, 17 (17/35 or 49%). Positive households were identified in Chito (l), Barra La Cruz (1) and El Chorro (3). In 2 of the 3 af- fected households in El Chorro, more than one family member had been affected; 4 members of one family had suffered from bleeding verrugas 2-3 years previously at which time 6-7 guinea-pigs had died; and 5 members had verruga peruana in the other family.

In the questionnaire the following variables were of increased frequency in case households compared to control households in communities where at least one case household had been identified; sick or dead chick- ens (P<O.O5), sick or dead guinea-pigs (not statistically significant), and the presence of ticks within the house (P<O.O5).

Fifteen cases had experienced verruga-like lesion/s in the last 5 years and samples were taken from them. In addition, 28 patients with fever and one with suspicious skin lesions were sampled; in none were B. bacilliformis detected in blood films or culture. All available school- age children (243) were bled in the communities of El Chorro (llO), Pucapamba (14), Barra La Cruz (71), and Chito (48). No evidence of current blood-borne infection with B. bacilliformis was seen. None of the children was anaemic (using US standard haemoglobin values accord- ing to age; DAYTON & PETERSON, 1995).

Discussion Human bartonellosis was first noted in Zamora

Chinchipe province in 1937 (ALVARADO COBO, 1942) and subseouent outbreaks were renorted in 1938. 1940 (LEON & LEON, 1986), and 1944 [BONILLA, 1944). Be- tween 1944 and 1978, the disease seems to have been sporadic, with a total of 27 cases reported, principally in military recruits garrisoned on the frontier (BERRU CUEVA, 1954; LEON & LEON, 1986). Small outbreaks were reported in 1980 (V. Reyes, unpublished report) and 1984-1985 (Ephraim Beltran, personal communica- tion). B. bacilliformis was detected in blood films from patients in both the latter outbreaks. The communities most affected were Zumba, El Chorro, Chito, and La Chonta. In this study we were able to identify patients who had exnerienced verruga peruana-like eruptions in 1992 in the-communities o-f El Chorro, Barra La Cruz, and Chito. The finding of several members of 2 families suffering from this skin eruption is highly suggestive. However, none of the inhabitants of these communities who were sampled had a positive blood film or culture.

The failure to find human bartonellosis in this study might be explained by several factors. The incidence of bartonellosis in Zamora Chinchipe is closely related to

the rainy season and is maximal towards its end (A. Cac- eres, personal communication). When our study was performed, the winter had been unusually dry. It is also possible that the study was performed in an inter- epidemic period when cases may be undetectable (HER- RER, 1990). There are many parallels between the disease seen in Zamora Chinchipe and that seen in the adjacent Peruvian province of San Ignacio. There, case numbers peak every 10 to 15 years in mini-epidemics (G. Huatuco, personal communication). The easy availabil- ity of antibiotics in the pharmacies of even the smallest villages, as well as the widespread spraying of DDT or malathion for the control of malaria, are likely to have significantly altered the epidemiology of bartonellosis in Ecuador. For example, long-term spraying of residual insecticides in Peru has transformed it from an endemic disease to a snoradic one (HERRER, 1990).

The findings of asymptomatic infection in up to 10% of individuals living in endemic areas has suggested that humans are the reservoir of infection (HE<&R, 1990). However, a number of observations suggest that humans may not be the natural reservoir: (i) there are reports of individuals acquiring the disease in uninhabited areas (TOWNSEND, 1913; HERRER, 1990); (ii) an increase in the rodent population, and illness or death of domestic animals such as guinea-pigs, have been described before disease outbreaks (GRAY et al., 1990); (iii) inhabitants of endemic areas claim that domestic animals are suscepti- ble to bartonellosis and often develop verruga-like nod- ules (SHANNON. 1929: GAMARRA. 1964): (iv) organisms resembling B. dacdl~$iirmis have been is&ted fr<m wild rodents such as Phyllotis spp. (HERTIG, 1948) and guinea- pigs in endemic areas (WEINMAN & PINKERTON, 1937); (v) bartonellosis can be induced in species of mammals other than humans, including monkeys, dogs, donkeys, rabbits and guinea-pigs (reviewed by HERRER, 1990); and (vi) the presence of asymptomatic human infection is seasonal and disappears during the ‘dry’ season (HER- RER, 1953). The absence of infection in this study in the age groups which suffer verruga peruana in endemic ar- eas (e.g., children) also suggests that humans are not the reservoir. The questionnaire survey suggested a relation- ship between case households and sick or dead chickens and guinea-pigs. These animals may be the domestic res- ervoir of disease. The natural reservoir of disease mav be wild rodents, such as Phyllotis. Outbreaks of bartohel- losis may occur when a large reservoir of susceptible hu- mans coincides with circumstances which favour trans- mission. For example, in Peru epidemics have occurred when severe summer rains have resulted in the flooding of towns and the temporary migration of people into neighbouring verruga-endemic hills (HERRER, 1990).

The association of the presence of ticks in case house- holds is likely to be spurious. Though some early work- ers incriminated ticks as possible vectors (TOWNSEND, 1913; NOGUCHI, 1926), more convincing evidence exists of the role of sandflies. narticularlv L. verrwarum. in dis- ease transmission (reviewed by *HERRER, 1990). Most case households were lcoated outside towns and were surrounded by forest or cultivated land where ticks are more likely to be abundant.

Acknowledgements This study was financed by the Wellcome Trust. Drs David

Gaus, Euhraim Beltran, Richard Birtles, and Andv Hall are thanked- for their advice and assistance. The communities which participated in this study are also thanked for their co- operation.

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Received 31 October 199.5; revised 4 December 1995; ac- cepted for publication 5 December 199.5

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