[Attempted infection of Chad goats by bovine infections rhinotracheitis virus. Serological survey in West Chad].
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Animals↗
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[Human echinococcosis in Chad, a breeding country (3 cases at Fort-Lamy, Chad)].
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Adult↗
A survey of hemoglobins in the Republic of Chad and characterization of hemoglobin Chad:alpha-2-23Glu--Lys-beta-2.
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Adolescent↗
Hb Chad or alpha 223(B4)Glu----Lys beta 2 observed in members of a Surinam family in association with alpha-thalassemia-2 and with Hb S.
Three different hemoglobinopathies, i.e. Hb S, Hb Chad [alpha 23 (B4)Glu----Lys], and alpha-thalassemia-2 (-3.7) have been observed in eight members of a family from Surinam. The proposita had all three abnormalities, while her mother and four of her half-brothers had Hb Chad together with an alpha-thalassemia-2 heterozygosity or homozygosity. Gene mapping and dot-blot analysis of amplified DNA identified a G----A mutation in codon 23 of the alpha 2 alpha 1 hybrid gene resulting in the Glu----Lys substitution. The quantity of the alpha-Chad chain averaged 31.5% in its carriers with an additional alpha-thalassemia-2 heterozygosity [-alpha Chad(-3.7 kb)/alpha alpha], and 43% in the two carriers with an additional alpha-thalassemia-2 homozygosity [-alpha Chad (-3.7 kb)/-alpha (3.7 kb)]. These quantities are considerably higher than those reported for families from Chad, China, and Japan; the low levels of 14.5-24% Hb Chad in members of previously reported cases suggest a mutation on a chromosome with two alpha-globin genes [alpha alpha Chad/alpha alpha or alpha Chad alpha/alpha alpha].
Adult↗
Changes in the pancreatic A-, B- and D-cell populations during development of diabetes in spontaneously diabetic Chinese hamsters of the Asahikawa colony (CHAD).
We investigated the pathological changes in pancreatic islets during the development of diabetes in spontaneously diabetic Chinese hamsters of the Asahikawa colony (CHAD), using morphometric analysis and specific immunocytochemical methods. We also investigated the relationships between changes in islet cell composition and the hormonal changes in the plasma and pancreas. Plasma and pancreatic insulin levels were significantly lower in diabetic hamsters than in pre-diabetic hamsters. However, plasma insulin levels in the pre-diabetic hamsters were significantly higher than those in the hamsters from the non-diabetic control strain, although the pancreatic insulin content in the pre-diabetics was significantly lower than that in the non-diabetics. Since even a severely diabetic CHAD is alive for many months after the onset of the disease without injections of insulin, its clinical course seems to be close to that of type 2 human diabetes. In contrast, plasma and pancreatic glucagon levels were significantly higher in diabetic hamsters than in non-diabetics and pre-diabetics. There were significantly positive correlations between plasma and pancreatic insulin, and plasma and pancreatic glucagon levels in CHAD (P less than 0.01). On the other hand, no significant differences in the pancreatic somatostatin content were found among the non-diabetics, pre-diabetics, and severe diabetics. Significant correlations were found between plasma and pancreatic hormone levels (except for somatostatin) and the advance of diabetes in CHAD (P less than 0.01). Morphometric analysis by planimeter revealed that islets in the severe diabetics were 25% smaller than in the pre-diabetics. Significantly less B-cell area within the diabetic islets was found when compared with the non-diabetic and pre-diabetic islets. Significantly larger A- and D-cell areas within the diabetic islets were found compared with the non-diabetic and pre-diabetic islets. There was a significant correlation between the areas of the three types of cell within the islets and the severity of diabetes (P less than 0.01). It is suggested, therefore, that the pancreatic islet function in CHAD is closely associated with the morphologic changes in islet endocrine cells. The elevation of plasma and pancreatic glucagon levels and the marked increase of the A-cell area within the islets from severely diabetic CHAD may reveal an absolute increase of A-cell numbers.
Animals↗
Cisplatin-MECY (methotrexate-leucovorin rescue plus cyclophosphamide) versus cisplatin-CHAD (cyclophosphamide, hexamethylmelamine, doxorubicin, and cisplatin) as initial chemotherapy in stage III-IV ovarian adenocarcinoma.
Thirty-three patients with advanced-stage ovarian adenocarcinomas, with no prior chemotherapy, were treated with weekly cisplatin (DDP) for four courses followed by five monthly courses of one of two randomly assigned multidrug combinations. These combinations were high-dose methotrexate-leucovorin plus cyclophosphamide (MECY) or cyclophosphamide, hexamethylmelamine, doxorubicin, and DDP (CHAD). Patients with no clinically measurable disease after 6 months of therapy were evaluated by laparoscopy. In the absence of disease progression at the time of the laparoscopy the study design called for a repeat cycle of four weekly DDP courses and another five monthly courses of the assigned multidrug combination. All patients with no evidence of disease after 1 year of treatment had a second-look laparoscopy which, if negative, was followed by a second-look laparotomy. This report includes all of the consecutively entered patients observed for a minimum of 1 year or to death. DDP-MECY and DDP-CHAD were similarly active for overall response rates and complete response rates according to laparoscopic criteria. However, DDP-MECY had a statistically significantly lower relapse rate (P less than 0.02) and a statistically significantly higher negative second-look laparotomy rate than did DDP-CHAD. Using all entered patients, with no exclusions from analysis, eight of 17 patients (47%) treated with DDP-MECY had negative second-looks after 1 year of treatment. This compares with one of 16 (6%) negative second-looks in patients treated with DDP-CHAD (P less than 0.02). The high negative second-look rate with DDP-MECY is exciting. Positive cytologic washings at the 6-month laparoscopic evaluation were highly predictive that residual disease would be found at the 1-year second-look surgery. Only one patient with positive peritoneal cytology after 6 months of treatment was found to have a negative second-look after 1 year of therapy.
Adenocarcinoma↗
Characterization of hepatitis E virus (HEV) from Algeria and Chad by partial genome sequence.
The purpose of this study was to analyze partial nucleotide sequences and derived peptide sequences of hepatitis E virus (HEV) from two outbreaks of hepatitis E in Africa (Chad 1983-1984; Algeria 1978-1980). A portion of ORF3 and the major portion of ORF2 were amplified by Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR). The PCR products were sequenced directly or after cloning into the pCRII vector. Sequences were then compared to the corresponding regions of reported full length HEV sequences. In the ORF2 and ORF3 regions, the homology between the Algerian and the Chad isolates at the nucleic acid level was 92 and 95%, respectively. At the peptide level the homology was 98% in both regions. In these regions, both strains are more related to Asian strains at the nucleic acid level (89 to 95%) and at the amino acid level (95 to 100%) than to the Mexico strain. At the peptide level the differences are less apparent. Both African isolates have amino acid changes in common with some reference strains although the Chad isolate has three unique changes. These African strains of HEV, based on the ORF2 and ORF3 phylogenetic trees, appear to be a distinct phylogenetic group, separate from the Mexican and Asian strains.
Algeria↗
The first australopithecine 2,500 kilometres west of the Rift Valley (Chad)
The first sites with Pliocene and Pleistocene mammals west of the Rift Valley in Central Africa in northern Chad were reported in 1959 (ref. 1), and documented the presence of mixed savannah and woodland habitats. Further sites and a probable Homo erectus cranio-facial fragment were subsequently discovered. In 1993 a survey of Pliocene and Pleistocene formations in the Borkou-Ennedi-Tibesti Province of Chad (B.E.T.) led to the discovery of 17 new sites in the region of Bahr el Ghazal (classical Arabic for River of the Gazelles) near Koro Toro. One site, KT 12 (15 degrees 58'10"N, 18 degrees 52'46"E) yielded an australopithecine mandible associated with a fauna biochronologically estimated to be 3.0-3.5 Myr old. Australopithecine species described since 1925 are known from southern Africa and from sites spread along the eastern Rift Valley from Tanzania to Ethiopia (Fig. 1). This new find from Chad, which is most similar in morphology to Australopithecus afarensis, documents the presence of an early hominid a considerable distance, 2,500 km, west of the Rift Valley.
Adult↗
Role of hepatitis E virus in sporadic cases of acute and fulminant hepatitis in an endemic area (Chad).
Forty-one patients with acute or fulminant hepatitis and 86 control patients were entered into a study of sporadic, acute, and fulminant hepatitis in the N'Djamena area of Chad in 1993. Acute hepatitis B was diagnosed in nine (22%) patients and acute hepatitis E in 27 (66%) patients. No acute hepatitis A was observed and 10% of the patients had serologic markers of hepatitis C virus (HCV) infection. Dual acute hepatitis B and E were observed in four patients (10%) and acute HEV infection was associated with chronic hepatitis B surface antigen carriage in 16 (39%). Epidemiologic findings concerning HBV from Chad suggest that these patients had undiagnosed chronic liver disease due to HBV, with acute deterioration caused by superimposed HEV replication. Moreover, it is obvious that in developing countries only the most severe cases of hepatitis are seen in hospital settings and a large proportion of them are related to superinfection with HBV and HEV. Antibody to HEV was observed in 22% of the control patients. This observation and the fact that epidemic and sporadic cases of HEV are observed in Chad indicates that HEV is highly endemic in this country.
Acute Disease↗
[History of the public health policy in Chad 1900-1995].
Public health policy in Chad began after colonization in 1899 and remained under the control of French Army Medical Corps for a long time. Military doctors shared their time between treating service personnel and indigenous people entitled Medical Assistance and making rounds in their sector. Since independence public health in the country has been based on a two-pronged association including fixed facilities (hospitals and dispensaries) and mobile services such as the Endemic Disease Unit whose most notable success was control of sleeping sickness in the southern part of the country. Over the years Chad has built up a national medical staff comprising 150 physicians. A medical school was opened in N'Djamena in 1990 and paramedical personnel are now trained at the National School for Public Health. War and lack of funds interrupted mobile services and there is presently a recrudescence of sleeping sickness. Since 1990 the World Health Organization has imposed its views and primary care is now available for all. However, it is now too early to judge the efficacity of this program in Chad.
Chad↗
The CHAD and HAD regimens in advanced ovarian cancer: combination chemotherapy including cyclophosphamide, hexamethylmelamine, adriamycin, and cis-dichlorodiammineplatinum(II).
Combination chemotherapy consisting of hexamethylmelamine, adriamycin, and cis-dichlorodiammineplatinum(II) was given to 27 patients with advanced epithelial ovarian cancer whose disease had progressed while receiving therapy including alkylating agents. Eighteen patients (67%) had objective partial or complete remissions for a projected median duration of 7 months. Based on this high level of activity in this poor-risk group, the three drugs were combined with cyclophosphamide in a four-drug regimen (CHAD) for initial therapy suitable for outpatient administration. Nineteen of 21 evaluable patients (90.4%) receiving CHAD responded. Complete clinical remissions were noted in ten patients (47.6%) and were confirmed at "second-look" laparotomy in two of these. An additional five patients without evaluable disease after initial surgery are free from relapse at 4--15 months. Toxicity was only moderately severe; 28% of the patients had wbc counts less than 2000/microliters at some point. Nephrotoxicity from cis-dichlorodiammineplatinum(II) was almost completely prevented by a 2-hour outpatient regimen of hydration and diuresis. A prospective randomized trial is planned comparing CHAD to melphalan in previously untreated women with advanced ovarian cancer.
Adult↗
Prevalence of iodine deficiency disorders and goitre in Chad.
A nationwide sample survey was conducted in Chad to establish the prevalence of iodine deficiency disorders (IDD). The country was stratified into the Sahel zone and the Sudan zone, the latter including the city of N'Djamena. The analysis followed a stratification whereby the city of N'Djamena was also separately analysed. A total of 1171 people between 10 and 20 years of age were included in the survey. The overall weighted prevalence of goitre, evaluated by a clinical examination, was 63%. In the Sudan zone the prevalence was 70%, in the Sahel zone 64% and for the capital, N'Djamena, 25%. There were significant differences in the frequency of goitre between the three zones. Females-as established in surveys from other areas and countries-had goitre significantly more often. The prevalence of cretinism varied between 0 and 1.2%, and was highest in the Sahel zone. Amongst the sampled population of the Sudan zone, 33% had less than 20 micrograms/l of urinary iodine, indicating severe iodine deficiency. In the Sahel zone and in N'Djamena the figures reached 8 and 1%. There were high levels of thiocyanate anions in urine reaching medians between 21 and 27 mg/l in the geographical stratas. This probably decreases the bio-availability of iodine. These data show that there is a high endemicity of goitre in Chad and provide a basis for interventions as part of a national action plan against IDD, which will be adapted to the social, cultural and economic situation of the country and to available health services.
Adolescent↗
[Note on the lessons of rinderpest control in Chad since 1935].
The policy of rinderpest control in Chad has passed through various phases over sufficiently long periods to validate certain concepts such as that of the usefulness of perifocal vaccination of populations which have not been previously vaccinated. After studying the reliability of data regarding livestock, vaccinations and pathology and after having reviewed the various types of vaccine used, it can be concluded that perifocal vaccination, even in conjunction with the systematic vaccination of young, has not enabled rinderpest to be brought under control in Chad. Only systematic livestock vaccination can control and eradicate the disease. A table illustrates the vaccination operations and monitoring systems used.
Animals↗
[Comparison of the pathogenic effect in mice between stocks of Trypanosoma evansi from Mauritania and from Kenya, Niger, Chad and China].
The pathogenicity to mice of a stock of Trypanosoma evansi from Mauritania has been compared to that of stocks from Kenya, Niger, Chad and China, using doses of 5.10(5), 2.10(6) and 5.10(6) trypanosomes per mouse. The survival of mice inoculated with stocks from Kenya, Niger and China is short, on average 2.1 to 6.5 days. Mice inoculated with stocks from Mauritania and Chad survive longer, 12.5 to 22.7 days, depending on the dose.
Animals↗
[First- time isolation of the peste des petits ruminants (PPR) virus in Chad and experimental induction of the disease].
In Chad, in 1993-1994, investigation into "peste des petits ruminants" (PPR) outbreaks were carried out in flocks of Sahelian goats. Although in the early 1993 outbreaks the virus had not been isolated yet, a serological prevalence (34%) was observed using ELISA test in 475 sera collected in the infested area. The virus was then isolated for the first time in Chad and typical PPR cases were observed in Sahelian goats, known to be little sensitive to the virus. To experimentally induce the disease, goats were inoculated with suspensions of lymph nodes or lungs, collected from sick animals. Lung suspensions induced the most serious symptoms. Suspensions of lungs and mesenteric lymph nodes were positive by agar-gel immunodiffusion test against PPR anti-serum, while prescapular lymph nodes remained negative. Characterization of the isolated virus, in particular with regard to its genomic identity, should be investigated.
Animals↗
Long-chain 3-hydroxyacyl-coenzyme A dehydrogenase (L-CHAD) deficiency in a patient with the Bannayan-Riley-Ruvalcaba syndrome.
Bannayan-Riley-Ruvalcaba syndrome (BRRS) is an autosomal dominant condition of macrocephaly in combination with lipomas/hemangiomas, hypotonia, developmental delay, and a lipid myopathy. The etiology of the lipid storage myopathy has been unclear. We describe a black boy with findings of BRRS who also has a defect in long-chain fatty acid oxidation expressed in cultured skin fibroblasts as a deficiency of long-chain-L-3-hydroxyacyl-CoA dehydrogenase (L-CHAD). He also has an abnormal brain MRI and increased size of both lower limbs. We present this child because of his unusual combination of findings, and postulate that L-CHAD deficiency may be the cause of the lipid myopathy in BRRS.
3-Hydroxyacyl CoA Dehydrogenases↗
Integrated Seroprevalence and Genome-Based Study of SARS-CoV-2 Viral Strains in N'Djamena: Insights Into Chad's COVID-19 Epicenter.
The COVID-19 epidemic has shown regional variations in transmission and outcomes. As a primary hotspot in Chad, N'Djamena is crucial for comprehensive epidemiological investigation. Our study employed two methodologies: seroprevalence data collection and whole-genome sequencing of SARS-CoV-2 strains. This dual approach assessed population exposure and virus genetic diversity. Seroprevalence data indicated broader exposure than confirmed cases suggested, and genome sequencing identified multiple strains, including globally recognized variants of concern. Integrating these data provided insights into transmission dynamics, potential herd immunity thresholds, and the impact of specific variants on disease progression. Our findings underscore the importance of integrated, multidisciplinary research in infectious disease epidemiology and inform targeted public health strategies, including social measures and vaccination, to combat infectious diseases in N'Djamena.
Humans↗
[Preventive aspects and problems of a rural health project in Chad--the need for health motivation].
Some of the main difficulties encountered in health work in developing countries depend on the sociocultural conditions. Health animatiod until now) of rural health care. Its implementation requires the training and recycling of existing health personnel as well as of parts of the population. It includes the concept of "barefoot doctor", which corresponds well to the prevailing priority health needs. One should note potential difficulties, however, for example in regard to the way the barefoot doctor is to be remunerated (the author discusses some possibilities). It isn't easy either, in practice, to mobilize the community through health education and to obtain its participation in prevention and health promotion measures. The crucial element is to win its confidence. The author describes his practical experiences in Chad in this respect. Health animation stimulates the responsabilization and the development of a prospective outlook in people, and can thus make an important contribution to their overall development efforts. It is necessary to fight factors which slow down such an evolution, among which certain habits as well as obstacles of an administrative nature.
Chad↗