Search PubMed⌕ Search

Biomedical subjects

J Zinsstag

Publications and source records attributed to J Zinsstag.

At least 19 recordsLinked to original sources
PubMed2006

Species identification of non-tuberculous mycobacteria from humans and cattle of Chad.

In Chad, during a study on tuberculosis in humans and cattle, 52 non-tuberculous mycobacteria (NTM) strains were isolated. By means of INNO-LiPA, PRA-hsp65 amplification and sequencing of 16S rDNA, NTM species of 25/52 isolates were identified. M. fortuitum complex (8) was the most frequent species, followed by M. nonchromogenicum (4) and M. avium complex (4). PRA method could identify M. fortuitum 3rd variant among isolates derived from cattle specimens. This finding could confirm the existence of farcy in the Chadian cattle population as M. fortuitum 3rd variant and putitative pathogen M. farcinogenes can't be distinguished by the methods used in this study. Half of the NTM isolates could not be specified and we considered them as contaminants from the environment.

Animals↗
PubMed2006

Cost-description of a pilot parenteral vaccination campaign against rabies in dogs in N'Djaména, Chad.

In the discussion about policies and strategies for rabies prevention in developing countries, intervention costs arise as a major issue. In a pilot mass vaccination campaign against rabies in N'Djaména, Chad, 3000 dogs were vaccinated. We assessed vaccination coverage and cost, showing the cost per dog vaccinated for the public sector and for society. An extrapolation to city level calculated the approximate cost of vaccinating all 23 600 dogs in N'Djaména. In the pilot mass campaign with 3000 dogs the average cost per dog was 1.69 euro. to the public and the full societal cost was 2.45 euro. If all 23 600 dogs in N'Djaména were vaccinated, the average cost would fall to 1.16 euro to the public and 1.93 euro to society. Private sector costs account for 31% of the cost to vaccinate 3000 dogs, and 40% of the cost to vaccinate 23 600 dogs. Mass dog vaccination could be a comparatively cheap and ethical way to both control the disease in animals and prevent human cases and exposure, especially in developing countries. The cost-effectiveness of dog vaccination compared with treating victims of dog bites for prevention of human rabies should be further assessed and documented.

Animals↗
PubMed2005

A model of animal-human brucellosis transmission in Mongolia.

We developed a dynamic model of livestock-to-human brucellosis transmission in Mongolia. The compartmental model considers transmission within sheep and cattle populations and the transmission to humans as additive components. The model was fitted to demographic and seroprevalence data (Rose Bengal test) from livestock and annually reported new human brucellosis cases in Mongolia for 1991-1999 prior to the onset of a mass livestock-vaccination campaign (S19 Brucella abortus for cattle and Rev 1 Brucella melitensis for sheep and goat). The vaccination effect was fitted to livestock- and human-brucellosis data from the first 3 years of the vaccination campaign (2000-2002). Parameters were optimized on the basis of the goodness-of-fit (assessed by the deviance). The simultaneously fitted sheep-human and cattle-human contact rates show that 90% of human brucellosis was small-ruminant derived. Average effective reproductive ratios for the year 1999 were 1.2 for sheep and 1.7 for cattle.

Animals↗
PubMed2005

Morbidity and nutrition patterns of three nomadic pastoralist communities of Chad.

As a part of an interdisciplinary research and action programme, morbidity and nutritional patterns were assessed in three nomadic communities: Fulani and Arab cattle breeders and Arab camel breeders, of two prefectures in Chad. The predominant morbidity pattern of Chadian nomadic pastoralists (representing approximately 10% of the total population of the country) had not been documented so far. A total of 1092 women, men and children was examined by a physician and interviewed during two surveys in the dry season and one in the wet season (1999--2000). Participants with no complaint were rare. Pulmonary disorders (e.g. bronchitis) were most often diagnosed for children under 5 years of age. Of the adult participants, 4.6% were suspected of tuberculosis. Febrile diarrhoea occurred more often during the wet season when access to clean drinking water was precarious. Malaria was only rarely clinically diagnosed among Arabs during the dry season, whereas Fulani, who stayed in the vicinity of Lake Chad, were also affected during this period. A 24-h dietary recall showed that less Arab women than men consumed milk during the dry season (66% versus 92%). Malnutrition was only documented for 3 out of 328 children (0--14 years). Arab women in childbearing age had a higher proportion of children not surviving when compared to Fulani women (0.2 versus 0.07). This study identified several implications for reseach and interventions in nomadic settings. Innovative and integrated health services for nomads can possibly be extended to many settings as nomadic pastoralists have in common a similar way of life driven by the needs of their animals.

Adolescent↗
PubMed2005

Seroprevalence of Q-fever in febrile individuals in Mali.

OBJECTIVES: We conducted a serological survey for Q-fever among febrile patients in Bamako and Mopti (Mali) and investigated the main risk factors for seroconversion. METHODS: Blood samples from 156 febrile patients were collected in healthcare facilities of Bamako and Mopti and examined with the microimmunofluorescence test. RESULTS: Forty per cent (n = 63) were seropositive for Q-fever, 28% in Bamako and 51% in Mopti. A more recent infection was suspected in 9.5% (n = 6) of all seropositive patients. This is the first time that Q-fever seropositivity is reported in febrile individuals in Mali. The patients' symptoms and diagnoses spanned a wide range of conditions; none had been diagnosed with Q fever by their treating physician. No risk factors for seropositivity could be identified with the exception of the city of residence and none could be identified with a logistic regression model with 'city' taken as random effect. CONCLUSION: A high rate of seropositivity to C. burnetii was found among febrile urban patients in Mali but no risk factors for seropositivity could be identified in this study.

Adolescent↗
PubMed2005

[Impact of canine demography on rabies transmission in N'djamena, Chad].

A transversal study using the clustering technique was carried out in 600 households to estimate dog-population density in the city of N'Djamena and evaluate the knowledge of the inhabitants concerning the risk of rabies. Dog-population density as estimated by negative binomial modelling was 0.03 dogs per person. The dog population estimated taking into account the extrapolated human population for 2001 was at 23 575 dogs (95% confidence interval, 14579-37921 dogs). Three-fourths of inhabitants reported that they had heard of rabies. Most respondents knew some rabies symptoms such as frothing at the mouth, restlessness, and aggressivity. In case of dog-bite injury many respondents said that they would seek care in medical facilities, e.g., health-care centers, hospitals and veterinary clinics, but some said they would also use traditional remedies, witch-doctor services, and self-medication. More than half of the respondents believed that symptomatic rabies could be cured. Because of confinement and feeding needs stray dogs are common. The canine vaccination rate is low (19%) for various reasons including limited financial resources, absence of transportation, unavailability of vaccination facilities, ignorance and negligence. Since access to health care after exposure can be difficult, mass vaccination of dogs is the recommended strategy to control rabies in cities like N'Djamena. Cooperation of all those involved in rabies control is necessary to promote the education and awareness action necessary to promote canine vaccination and reporting of exposure cases to competent authorities.

Animals↗
PubMed2004

Bovine tuberculosis: an old disease but a new threat to Africa.

Bovine tuberculosis (TB) is a disease characterised by progressive development of specific granulomatous lesions or tubercles in lung tissue, lymph nodes or other organs. Mycobacterium bovis is the causative agent of the disease. Bovine species, including bison and buffaloes, are susceptible to the disease, but nearly all warm-blooded animals can be affected. All species are not equally susceptible to the disease; some are spill-over (end) hosts and others maintenance hosts. In Africa, bovine TB primarily affects cattle; however, infection in other farm and domestic animals, such as sheep, goats, pigs, dogs and cats, is not uncommon. Wild ruminants and carnivores are also affected and are the natural reservoirs of the infectious agent in the wild. Man is also susceptible to the disease, the highest risk groups being individuals with concomitant HIV/AIDS infection. In Africa, human TB is widely known to be caused by M. tuberculosis; however, an unknown proportion of cases are due to M. bovis. This infection in humans is under-reported as a result of the diagnostic limitations of many laboratories in distinguishing M. bovis from M. tuberculosis. None of the national reports submitted to the OIE and WHO by African member states mention the importance of M. bovis in human TB cases. Consumption of unpasteurised milk and poorly heat-treated meat and close contact with infected animals represent the main sources of infection for humans. This review attempts to examine the impact of bovine TB on the health of animals and humans.

Africa↗
PubMed2004

[Indentification of institutional factors affecting the well-being of sedentary and nomadic populations living in the Waza-Logone flood plain along the border between Cameroon and Chad].

This article describes an ongoing research project designed to compile a database to promote pastoral development in the lowlands along the Logone and Chari Rivers in Cameroon. A number of sedentary and nomadic populations depend on these flood plains south of Lake Chad for their livelihood. However the natural resources of the area undergo sharp seasonal variations and sometimes become the property of sedentary groups. As a result nomadic communities experience difficulty not only in gaining access to grazing lands and water but also to quality health care (hospital centers, effective medication). The purpose of this study was to define institutional requirements necessary to ensure access to health care resources for both nomadic and sedentary groups. The main problem for the nomadic population is that, unlike the now defunct pre-colonial structures, today's institutions are not compatible with the subsistence strategies of rural populations. These findings suggest that new institutional frameworks for natural resource management could indirectly improve the health status of nomadic pastoralist.

Cameroon↗
PubMed2004

[Morbidity patterns in three nomadic communities in Chari-Baguirmi and Kanem, Chad].

Within the framework of an multidisciplinary research and action program, morbidity patterns were assessed in three nomadic communities, i.e., Fulani, Arab cattle breeders and Arab camel breeders, living in Chari-Baguirmi and Kanem, Chad. This is the first data about the health of Chadian nomadic pastoralists who account for approximately 6% of the total population. A total of 1092 women, men and children were interviewed and examined in the course of three surveys carried out by a physician during the dry and rainy season. Nomads reporting no health problems were rare. Tuberculosis was suspected in 4.6% of adults after clinical examination and bronchopulmonary disorders in children less than five years of age. Febrile diarrhea was more prevalent during the wet season when access to clean drinking water was more difficult. Simple malaria was rarely diagnosed in Arabs during the dry season. In contrast simple malaria was frequent in Fulani who stay in the vicinity of Lake Chad during the dry period. Protein-energy malnutrition was observed in only 3 of 328 children younger than 15 years of age.

Adolescent↗
PubMed2004

[Seroprevalences of zoonotic diseases in nomads and their livestock in Chari-Baguirmi, Chad].

The seroprevalences of brucellosis and Q-fever were evaluated in humans and livestock in three Chadian nomadic communities, i.e., Fulani cattle breeders and Arab camel and cattle breeders. The survey was carried out in 1999 and 2000. The total number of human sera and animal sera tested were 911 and 1637, respectively, for antibodies against Brucella spp. and 368 and 613, respectively, for Coxiella burnetii. Sixteen brucellosis positive human sera resulted in a seroprevelance rate of 2%. Male participants were significantly more often brucellosis seropositive than females. No association was found between brucellosis serostatus and physical findings or reported symptoms. Positive brucellosis serology was more frequent in cattle (seroprevalence, 7%) than in camels (1.4%) and small ruminants (0.5%). Fifteen human sera from 11 Arab camel breeders and 4 Arab cattle breeders were positive for Q-fever (seroprevalence below 1%). Being a camel breeder was a significant risk factor for Q-fever seropositivity. Camels had the highest Q-fever seroprevalence (73%) among livestock species.

Brucellosis↗
PubMed2004

[First isolation of tuberculous mycobacteria in man and animals in Chad].

This report describes the first successful isolation and identification of mycobacterial infection in humans and animals of Chad. All mycobacterial strains from human specimens were M. tuberculosis and strains from animal specimens (cattle) were M. bovis. None of the 10 of M. tuberculosis strains tested for antibiotic resistance were multidrug resistant. Due to the intrinsic resistance of M. bovis to pyrazinamide and the growing number of tuberculosis cases in HIV-infected people in Africa and elsewhere, more information on the potential of M. bovis for human infection is needed to guide disease control policy.

Animals↗
PubMed2004

[Health care services for nomadic people. Lessons learned from research and implementation activities in Chad].

To overcome barriers of access to health care of nomadic people and to alleviate inequities in health, a transdisciplinary team has initiated research and intervention activities among three nomadic groups of Chad: Foulbé, Arabes and Gouranes. A regular and consistent communication among all actors involved (nomadic groups, researchers, planners and administrators of health and veterinary services, etc.) through repetitive meetings and workshops showed to be a crucial element for success. Differences between ethnic nomadic groups made it necessary to develop specific communication strategies adapted to each group. As to interventions to improve the vaccination coverage, mixed teams combining health and veterinary specialists were able to vaccinate an important number of children and women and showed to have a high potential in terms of organisational and logistic feasibility, acceptability as well as good cost-effectiveness. With regard to improving access to health care, Information--Education and Communication approaches adapted to the intervention context and linked to the provision of essential services and generic drugs showed to be crucial.

Adolescent↗
PubMed2004

[An innovative approach combining human and animal vaccination campaigns in nomadic settings of Chad: experiences and costs].

The purpose of this report is to describe a network of public health care workers, veterinarians and nomadic pastoralists that was set up in Chad to increase vaccination coverage to nomadic children and women who had rarely been vaccinated before. The objectives of the project were to provide human vaccination in conjunction with existing veterinary services, to evaluate the feasibility and limitations of such campaigns, to determine what other services could be provided concurrently, and to estimate the savings for public health care cases in comparison with carrying out vaccination separately. In a series of 12 vaccination campaigns in the Chari-Baguirmi and Kanem districts, more than 2100 children, 2100 women and 52000 cattle were fully immunized. These results confirmed the feasibility of joint campaigns in nomadic settings and provided important experience for improving organization. Information-Education-Communication (IEC) campaigns adapted to the realities of the pastoral setting were an important factor in mobilizing nomadic pastoralists for attendance at vaccination clinics. The savings in logistics costs (i.e., personnel, transportation and cold chain costs excluding vaccine costs) was 15% in Gredaya where 3 out of 6 campaigns were carried out together with veterinarians and 4% in Chaddra/Am Dobak where only 1 out of 6 campaigns was carried out in conjunction with veterinarians. The cost per fully immunized child (FIC) was considerably higher in Chaddra/Am Dobak than Gredaya (EUR 29.2 vs. EUR 11.5). The joint vaccination campaign approach is innovative, appreciated by nomadic pastoralists and less expensive than separate vaccination. By using the mobility of veterinarians in remote zones far from health care facilities, vaccination can be provided to nomadic children and women in countries with limited resources.

Adolescent↗
PubMed2003

Brucellosis and Q-fever seroprevalences of nomadic pastoralists and their livestock in Chad.

As a part of a research-and-action partnership between public health and veterinary medicine, the relationships between the seroprevalences of brucellosis and Q-fever in humans and livestock were evaluated in three nomadic communities of Chad (Fulani cattle breeders, and Arab camel and cattle breeders). Nomad camps were visited between April 1999 and April 2000. A total of 860 human and 1637 animal sera were tested for antibodies against Brucella spp., and 368 human and 613 animal sera for Coxiella burnetii. The same indirect ELISA was used for livestock and human sera, and the test characteristics for its use on human sera were evaluated. Twenty-eight people were seropositive for brucellosis (seroprevalence 3.8%). Brucella seroprevalence was higher in cattle (7%) than other livestock, and brucellosis seropositivity was a significant factor for abortion in cattle (OR=2.8). No correlation was found between human brucellosis serostatus and camp proportions of seropositive animals. Q-fever-seropositive blood samples were taken from 11 Arab camel and 4 Arab cattle breeders (seroprevalence 1%). Being a camel breeder was associated with Q-fever seropositivity in humans (OR=9). Camels had the highest Q-fever seroprevalence (80%) among livestock species. Although there was high-risk human behaviour for the acquisition of brucellosis and Q-fever from livestock through raw-milk consumption (98%) and contact with placentas of livestock (62%), we concluded that seroprevalences in humans were relatively low (likely due to limited active foci in livestock).

Adolescent↗
PubMed2003

Coverage of pilot parenteral vaccination campaign against canine rabies in N'Djaména, Chad.

Canine rabies, and thus human exposure to rabies, can be controlled through mass vaccination of the animal reservoir if dog owners are willing to cooperate. Inaccessible, ownerless dogs, however, reduce the vaccination coverage achieved in parenteral campaigns. This study aimed to estimate the vaccination coverage in dogs in three study zones of N'Djaména, Chad, after a pilot free parenteral mass vaccination campaign against rabies. We used a capture-mark-recapture approach for population estimates, with a Bayesian, Markov chain, Monte Carlo method to estimate the total number of owned dogs, and the ratio of ownerless to owned dogs to calculate vaccination coverage. When we took into account ownerless dogs, the vaccination coverage in the dog populations was 87% (95% confidence interval (CI), 84-89%) in study zone I, 71% (95% CI, 64-76%) in zone II, and 64% (95% CI, 58-71%) in zone III. The proportions of ownerless dogs to owned dogs were 1.1% (95% CI, 0-3.1%), 7.6% (95% CI, 0.7-16.5%), and 10.6% (95% CI, 1.6-19.1%) in the three study zones, respectively. Vaccination coverage in the three populations of owned dogs was 88% (95% CI, 84-92%) in zone I, 76% (95% CI, 71-81%) in zone II, and 70% (95% CI, 66-76%) in zone III. Participation of dog owners in the free campaign was high, and the number of inaccessible ownerless dogs was low. High levels of vaccination coverage could be achieved with parenteral mass vaccination. Regular parenteral vaccination campaigns to cover all of N'Djaména should be considered as an ethical way of preventing human rabies when post-exposure treatment is of limited availability and high in cost.

Animals↗
PubMed2003

Incidence of canine rabies in N'Djaména, Chad.

This work describes for the first time the incidence risk of passively reported canine rabies, and quantifies reported human exposure in N'Djaména (the capital of Chad). To diagnose rabies, we used a direct immunofluorescent-antibody test (IFAT). From January 2001 to March 2002, we were brought 34 rabies cases in dogs and three cases in cats. Canine cases were geographically clustered. The annual incidence risk of canine rabies was 1.4 (95% CI: 1.2, 1.7) per 1000 unvaccinated dogs. Most of the rabid dogs were owned-although free-roaming and not vaccinated against rabies. Most showed increased aggressiveness and attacked people without being provoked. Eighty-one persons were exposed to rabid dogs and four persons to rabid cats (mostly children<15 years old). Most of the exposed persons were neighbours or family members of the animal owner. Most exposures were transdermal bites, but nearly half of all exposed persons did not apply any first wound care or only applied a traditional treatment. In N'Djaména, humans are often exposed to canine rabies but do not use the full-course post-exposure treatment and wound care is insufficient. Most rabid dogs would be accessible to parenteral vaccination. Pilot vaccination campaigns are needed to determine the success of dog mass vaccination in N'Djaména as a way to prevent animal and human rabies.

Adolescent↗