Cord Blood Thyroid Stimulating Hormone Values in Healthy Term Babies delivered at Abubakar Tafawa Balewa University Teaching Hospital Bauchi, Northeastern Nigeria.

BACKGROUND: Congenital hypothyroidism is one of the most common preventable causes of mental retardation and clinical manifestations are often subtle or absent at birth and hence the need for screening. Implementation of newborn screening requires local normative values. OBJECTIVES: To determine the normative values of cord Thyroid Stimulating Hormone (TSH) among term babies in Bauchi, Northeast Nigeria and compare it with that from other centers in Nigeria. METHODOLOGY: Cord blood samples from 200 term babies were analyzed for TSH by Fluorescence Immunoassay technique in this descriptive cross-sectional study. A cut-off of >20 µIU/ml was used for recall. The mean and range were determined and compared with those of previous local studies using t-test. Impact of some maternal and infant factors on TSH was also assessed. RESULTS: The overall mean (SD) cord TSH was 3.74 (±1.99) µIU/ ml and the range was 0.73 to 15.22 µIU/ml (2.5th to 97.5th centile) and none had TSH > 20 µIU/ml and hence our recall rate was 0%. The mean cord TSH was comparable to that reported by a lone local multicenter study (p = 0.120) but significantly different from that of 3 other local studies (p < 0.001). There was also no significant difference between the means of different gender, birth weight groups, mode of delivery, socio-economic classes, maternal age and parity. CONCLUSION: The Cord blood TSH level of most term newborn in Bauchi, similar to other Nigerian studies, is < 10 µIU/ml with a few but significant percentage recording cord TSH level > 10 µIU/ml. Gender, birth weight, mode of delivery, socio-economic class, maternal age and parity were not significantly related to cord TSH level. The mean blood TSH values from different studies across the country tend to vary based on the assay technique. We recommend a nationwide multicenter study with a much larger sample size, lower cutoff value for recall and a unified sample processing laboratory if national normative values are to be developed.

BACKGROUND: L'hypothyroïdie congénitale est l'une des causes évitables les plus courantes de retard mental et les manifestations cliniques sont souvent subtiles ou absentes à la naissance, d'où la nécessité d'un dépistage. La mise en œuvre du dépistage néonatal nécessite des valeurs normatives locales. OBJECTIFS: Déterminer les valeurs normatives de l'hormone stimulatrice de la thyroïde (TSH) du cordon chez les bébés nés à terme à Bauchi, Nord-Est du Nigeria et les comparer à celles d'autres centres du Nigeria. MÉTHODOLOGIE: Des échantillons de sang ombilical de 200 bébés nés à terme ont été analysés pour la TSH par la technique d' étude descriptive transversale. Un seuil de >20 µUI/ml a été utilisé pour le rappel. La moyenne et l'intervalle ont été déterminés et comparés avec ceux des études locales précédentes en utilisant le test t. L'impact de certains facteurs maternels myet infantiles sur la TSH a également été évalué. RÉSULTATS: La moyenne globale (SD) de la TSH du cordon était de 3,74 (±1,99) µIU/ml et l'intervalle était de 0,73 à 15,22 µIU/ml (2,5 à 97,5 centiles) aucun n'avait une TSH > 20 µIU/ml et donc notre taux de rappel était de 0%. La moyenne de TSH au cordon était comparable à celle rapportée par une seule étude multicentrique locale unique (p = 0,120) mais significativement différente de celle de 3 autres études locales (p < 0,001). Il n'y avait pas non plus de différence significative entre les moyennes des différents sexes, groupes de poids de naissance, mode d'accouchement, classes socio d'accouchement, les classes socio-économiques, l'âge maternel et la parité. CONCLUSION: Le niveau de TSH dans le sang de cordon de la plupart des nouveau-nés à termede la plupart des nouveau-nés à terme à Bauchi, comme dans d'autres études nigérianes, est < 10 µUI/ml mais significatif, enregistrant un niveau de TSH du cordon > 10 µIU/ml. Le sexe, le poids à la naissance, le mode d'accouchement, la classe socio-économique maternelle et la parité n'étaient pas significativement liés au taux de TSH au cordon. Le site valeurs moyennes de la TSH sanguine provenant de différentes études dans le pays ont tendance à varier en fonction de la technique de dosage. Nous recommandons une étude nationale multicentrique avec une taille d'échantillon beaucoup plus grande, une valeur seuil pour le rappel et un laboratoire de traitement des échantillons unifié si des valeurs normatives nationales doivent être développées. Mots clés: Sang de cordon, Hormone de stimulation thyroïdienne, Bébés à terme.

Evaluating Ultrasound Determined Thyroid Volume as a Predictor of Newborn Thyroid Hormone Function.

BACKGROUND AND OBJECTIVES: Congenital hypo-thyroidism is a cause of intellectual and developmental disabilities in the newborn. Early screening and prompt treatment can prevent the devastating outcomes of congenital hypothyroidism. The disease burden of congenital hypothyroidism in Nigeria is higher than in many parts of the world. Using ultrasound, the authors sought to determine the normal mean thyroid gland volume in newborns and establish the thyroid gland volume as a predictor of thyroid hormone function in the newborn. METHODS: This was a descriptive cross-sectional study. Healthy newborns had their length and weight measured, thyroid ultrasound scan performed, and a blood sample taken for thyroid-stimulating hormone values. RESULTS: The mean total thyroid volume was 0.51cm3 ± 0.25. The thyroid volume of the right lobe (mean volume= 0.27cm3 ± 0.13) was significantly larger than the volume of the left lobe (mean volume =0.24cm3 ± 0.12) (p<0.001). The thyroid-stimulating hormone (TSH) values ranged from 1.36µIU/ml to 35.03µIU/ml with a mean value of 7.73µIU/ml ± 7.04. There was no significant correlation between the thyroid volumes and the TSH of the newborns. CONCLUSION: This study determined the mean thyroid volume in newborns. There was no significant correlation between the thyroid volumes and the TSH values of the newborns implying that the thyroid gland volume is not a reliable predictor of thyroid hormone function. Newborn, Ultrasound.

Charge syndrome in a Nigerian infant: a rare genetic disorder.

BACKGROUND: Charge syndrome is a rare genetic disorder that arises during early fetal development and affects multiple organ systems. Diagnosis is largely clinical. Mutation at the CHD7 gene located on Chromosome 8 has been identified in a great number of patients reviewed in different parts of the world. Survival depends on the intensity of the medical management as well as an early aggressive approach to the feeding adaptation in these children. CASE REPORT: We report a case of a 42 day old baby with clinical features in keeping with Charge syndrome. He was a product of a full-term uneventful pregnancy period delivered to non consanguineous apparently healthy parents. Two older siblings were normal. He developed respiratory distress shortly after birth. Multiple abnormalities were identified at birth which included genital, ear, eye and cardiovascular as well as skeletal abnormalities. Genetic testing was not carried out due to cost. Child was managed by a multidisciplinary team. Main problems were those of sepsis and feeding adaptation. He later succumbed to death after a month on admission. CONCLUSION: This is the first case of Charge syndrome reported in Nigeria. It is a rare, multisystemic condition with grave health implications and early diagnosis and appropriate management could reduce morbidity and prevent mortality. This report is to increase awareness of this rare condition and to promote better identification and intervention of similar presentation in future.

A typical presentations of hypothyroidism and associated problems in Ibadan, Nigeria.

BACKGROUND: Hypothyroidism can present atypically making its recognition difficult especially in resource limited settings. CASE PRESENTATION AND MANAGEMENT: Two children presented with atypical features of hypothyroidism with resultant delay in diagnosis. Patient I presented with persistent respiratory distress, facial swelling and recurrent syncopal attacks. Cardiovascular examination was normal except for pulmonary hypertension. He did not respond to conventional supportive therapy and hypothyroidism was discovered much later. Patient II was a seven month old male infant with abdominal swelling, bilateral pitting leg oedema, poor weight gain and delayed developmental milestones. Examination revealed ascites and pericardial effusion. He was being managed for protein energy malnutrition until he was found to have hypothyroidism and was successfully managed with L thyroxin. CONCLUSION: A typical presentations of hypothyroidism in resource limited settings can result in delay in diagnosis and treatment which can lead to unnecessary morbidity and mortality. High index of suspicion and expertise are therefore required.

Penile size in healthy Nigerian newborns: country-based reference values and international comparisons.

AIM: To establish normal reference values for penile size in Nigerian newborn boys and to compare those values with standards from other populations. METHODS: A total number of 261 healthy newborn boys delivered at gestational ages of 28 weeks or more were enrolled in the study. Penile lengths and widths were measured within 72 h of birth. RESULTS: The mean (±SD) penile length in the 261 Nigerian males studied was 3.4 ± 0.48 cm, while the mean mid-shaft diameter was 1.2 ± 0.14 cm. Compared with data from other populations, Nigerian newborn boys had similar penile sizes to those reported for US Caucasian boys (mean 3.4 cm), but significantly greater penile sizes than those reported for boys from China and Hong Kong (mean 3.0 and 3.1 cm, respectively; both p < 0.001). There was a slight, but significant, difference in size between Nigerian and Malaysian boys, with Malaysian boys having greater penile sizes (mean 3.5 cm; p < 0.05). CONCLUSION: A Nigerian newborn with a penile length of <2.39 cm can be considered to have a micropenis.

Type 1 diabetes mellitus in a known sickle cell anaemia patient: a rare combination in Nigeria.

BACKGROUND: Sickle cell anaemia is a very common disease condition in Nigeria. Its co-existence with type 1 diabetes mellitus is however rare, with only a few cases having been reported in literature and only two children have been reported from Nigeria. The genetic basis for this has not been fully reviewed. This case represents one of the few documented of both type 1 diabetes mellitus (T1DM) and homozygous sickle cell disease co-existing in an individual. More research is necessary to identify the factors that influence this co-morbidity and its effects on disease progression and patient management. CASE REPORT: Q. O, a ten year old girl presented in October 2011 with 9 year history of recurrent bone pains, yellowness of the eyes and poor growth. She also had a short history of polyphagia, polydipsia and polyuria. Haemoglobin electrophoresis showed SS while a random plasma glucose done at least twice was greater than 200 mg/dl. There was no ketosis nor did she have any other adverse complications. She is currently being managed as a case of sickle cell haemoglobinopathy with T1DM. Her management has been hampered by severe financial constraints. CONCLUSION: This report seeks to increase the awareness of this rare co-existence in this environment, as well as to highlight the antecedent challenges in management.

Gastrointestinal tuberculosis in renal transplant recipients: case report and review of the literature.

Mycobacterium tuberculosis is an important opportunistic pathogen following renal transplantation and is often associated with adverse outcomes. Gastrointestinal tuberculosis (GITB) is an infrequent manifestation of TB but a potentially lethal one. We present a case of a renal allograft recipient with GITB 18 months after transplant and review other published cases to identify the typical presenting symptoms, risk factors, and natural history. Treatment of GITB is also discussed.

PREVALENCE OF BACTERAEMIA AMONGST CHILDREN WITH FEBRILE SEIZURES AT THE UNIVERSITY COLLEGE HOSPITAL, IBADAN.

BACKGROUND: Febrile seizures are common among children and these are known to result from the diverse aetiological factors, known to cause fever in children. OBJECTIVES: To determine the prevalence of bacteraemia amongst children with febrile seizures at the children's emergency room of the University College Hospital, Ibadan, Nigeria. METHODOS: This was a prospective study involving 147 children who were presented with febrile seizures over a period of 13 months at the University College Hospital Ibadan. They all had their blood cultures sample taken under aseptic conditions. Other investigations performed on them included a packed cell volume, full blood count and blood film for malaria parasite. RESULTS: A total of 83 males and 64 females with febrile seizures were studied. Their ages ranged from 4 to 60 months with a mean age of 26.35 + 13.76 months. Bacteraemia was diagnosed in 32(21.8%) of the cases. The predominant organism isolated from the blood of these patients was Staphylococcus aureus. CONCLUSION: Bacteraemia is a frequent finding in children with febrile seizures hence, it may be beneficial to carry out blood culture in such children on the suspicion of a probable bacterial infection.

An epithelioid variant of the BHK21 hamster fibroblast line and its transformation by polyoma virus.

An epithelioid variant, which forms characteristic colonies in soft agar medium, has been isolated from the BHK21/13 line of hamster fibroblasts. After infection with a high multiplicity of polyoma virus, a fraction of the cells is morphologically transformed. Transformation may be demonstrated in two ways: 1) When infected cells are grown on glass, dense colonies of transformed cells develop from the confluent monolayer of untransformed cells in which multiplication has stopped because of their contiguity. 2) In agar, colonies derived from transformed cells are larger and morphologically distinct from those formed by the untransformed cells. The variant cells produce tumors in hamsters. Their transplantability is increased by polyoma transformation. Transformed cells possess a new polyoma-specific cell antigen.

Anemia associated with feline leukemia virus infection in cats.

The types of anemia associated with natural and experimental feline leukemia virus (FeLV) infection in cats were investigated. In one experiment, 10 kittens were inoculated neonatally with Jarrett FeLV-1, an isolate of subgroup A; 6 developed anemia a few weeks later. This anemia was characterized by macrocytosis, normoblastosis, increased erythropoiesis in the bone marrow, and extramedullary hematopoiesis in the spleen. Anemia was transient and nonfatal and occurred before the onset of lympoid malignancy. The same type of anemia was also seen in 9 of 24 kittens inoculated with Jarrett FeLV-9 of subgroups A and B. A different form of anemai occurred in another experiment in which 10 kittens were inoculated with FeLV-C of subgroup C only. All 10 kittens developed a profound aplastic or erythroblastopenic anemia in which the bone marrow became depleted of erythroid tissue; all kittens died within 16 weeks, most as a direct result of anemia. In an experiment in which kittens were inoculated with FeLV-B of subgroup B only, no kitten showed anemia. Cats with naturally acquired, nonleukemic lymphosarcoma were also studied. Of 33 lymphosarcomas in which myelophthisis was excluded as a cause, 54% of the affected cats had anemia, the features of which were consistent with hemolytic origin. When virus could be grown from these lymphosarcomas, it was of subgroup A alone or a combination of A and B. With one exception, anemic cats had low or negative titers to feline oncornavirus-associated cell membrane antigens. Until more isolates have been tested, it is not known if the various hematologic changes reflected differences in the pathogenic effects of the subgroups of the virus or of types of strains within them.

B and T cells in a cat with thymic lymphosarcoma.

The mixed antiglobulin reaction and the formation of nonimmune rosettes with guinea-pig red blood cells (RBC) distinguished feline B and T cells, respectively. In a cat with thymic lymphosarcoma, the cells reacting in these tests formed separate, nonoverlapping populations. The malignant cells were large lymphoblasts replacing the normal thymus and infiltrating local lymph nodes, where they localized only in the paracortical, i.e., thymus-dependent areas. Cells from the nodes could therefore be identified as malignant or normal by their size. The mixed antiglobulin reaction showed that the malignant cells did not carry the surface Ig characteristic of B cells, whereas these malignant cells formed nonimmune rosettes with guinea-pig RBC. Among lymph node cells, most surviving normal and small lymphocytes, from outside the thymus-dependent areas, reacted as B cells. The morphologic evidence therefore corroborated the test results, which indicated that the formation of rosettes with guinea-pig RBC seems a reliable means for the demonstration of T cells in the cat.

Feline oncornavirus-associated cell membrane antigen. IV. Antibody titers in cats with naturally occurring leukemia, lymphoma, and other diseases.

Cats with naturally occurring leukemia and lymphoma had low or negative humoral antibody titers to the feline oncornavirus-associated cell membrane antigen (FOCMA). Geographic differences were seen in the relative frequencies of various forms of lymphoproliferative neoplasms. Lymphatic leukemia and thymic lymphoma were most common in Boston, whereas alimentary lymphoma was most frequent in Glasgow. No significant differences were found in geometric mean FOCMA antibody titers for the various forms of leukemia-lymphoma or for feline leukemia virus (FeLV)-positive as compared to FeLV-negative cats. Approximately 70% of 76 Boston cats with nonregenerative anemias were FeLV gs antigen (gsa) positive; this was similar to the percentage with leukemia-lymphoma from the same population that was positive. Fifty-five to 62% of the Boston cats with other infectious diseases, such as peritonitis and septicemia, were gsa positive. We postulate that this is due to a predisposition to infectious diseases by the immunosuppressive action of FeLV. Young cats from the Boston population that developed lymphoma, infectious peritonitis, and certain other diseases were more likely to be FeLV gsa positive than older cats with the same diseases.

Biology of feline leukemia virus in the natural environment.

The feline leukemia virus (FeLV) was discovered in 1964 in a cluster of cats with lymphosarcoma. The observed clustering of cases of feline lymphosarcoma suggested that FeLV was an infectious agent for cats. The development of a simple immunofluorescent test for FeLV permitted a seroepidemiological study to be undertaken on the distribution of the virus in cats living in their natural environment. Over 2000 cats were tested, and the results showed conclusively that FeLV is an infectious agent for cats. This finding has now been independently confirmed using three different test procedures. After the infectious nature of FeLV was discovered, a simple FeLV test and removal program was devised to control the spread of the virus in the natural environment. The spread of FeLV was controlled in 45 households by removing the FeLV-infected cats, while in 25 households, where the infected cats were left in contact with the uninfected cats, 12% of the uninfected cats became infected. The ultimate control of FeLV awaits the development of an effective FeLV vaccine, which now seems feasible since we have already experimentally immunized some cats with attenuated FeLV. Although FeLV is infectious for cats there is no evidence that FeLV can infect humans.

Pathogenicity of feline leukemia virus is commonly associated with variant viruses.

Many of the serious diseases resulting from feline leukemia virus (FeLV) infection are associated with the generation of novel variant viruses. The prototype FeLV-A virus is highly stable and circulates in the cat population without apparent antigenic change. However, recombination with cellular oncogenes produces viruses which cause leukemia or other malignant diseases. Other recombinants within the env genes of FeLV-A and endogenous FeLV are recognized as belonging to a second subgroup, FeLV-B, the presence of which is correlated with an increased risk of infection with FeLV and a higher incidence of leukemia. Mutants of FeLV which affect the env gene are phenotypically of a third subgroup, FeLV-C, and have a close association with erythroid aplasia. None of these viruses, apart from FeLV-B, is transmitted further in nature. Therefore the generation of these novel viruses and the production of disease is an inadvertent consequence of FeLV infection.

Serological responses of cats to feline immunodeficiency virus.

The proteins of feline immunodeficiency virus (FIV) were identified by sodium dodecylsulphate poly-acrylamide gel electrophoresis (SDS-PAGE) and immunoblotting. Purified [35S]methionine/cysteine-labelled virus contained proteins of Mr 120, 24, 17, and 10kD, of which the most prominent were p24 and p17, and minor components of 62, 54, 52, 41 and 32kD. Sera from FIV-infected cats precipitated two glycoproteins (gp) of Mr 120kD (gp120) and 41kD (gp41) from lysates of [14C]glucosamine-labelled infected cells. Purified virus contained very little or no detectable glycoproteins. The serological response to individual viral proteins was followed in experimentally infected cats by immunoblotting. Since purified virus was a poor source of gp120, a method using FIV-infected cell lysates was developed. Cats produced antibodies to gp120, p55, p24 and p17. (The p55 was presumed to be a precursor of p24 and p17.) Following infection, antibodies developed first to p24 and subsequently to p17, p55 and gp120. Sera from cats infected with three separate isolates of FIV, two from the UK and one from the USA, had cross-reacting antibodies to all of these viral proteins. The criteria for identification of seropositive cats were defined. The minimum requirement for a positive immunoblot was antibody to gp120 or to at least three core proteins (p55, p24 and p17). Comparison of two commercial enzyme-linked immunosorbent assay (ELISA) kits and immunoblotting indicated that false-positive results occurred as a result of non-specific reactions in the ELISA systems.

Productive infection of T-helper lymphocytes with feline immunodeficiency virus is accompanied by reduced expression of CD4.

An antigen-specific feline T-lymphocyte cell line (Q201) was generated and infected in vitro with the feline immunodeficiency virus (FIV). Syncytium formation and the release of the viral core protein p24 into culture fluid were accompanied by a reduction in expression of the CD4 surface antigen. The reduction in CD4 expression was transient, the resulting persistently infected population of cells expressing levels of CD4 comparable to those observed prior to infection. Persistently infected cells gradually lost expression of major histocompatibility antigen (MHC) class II while maintaining pre-infection levels of expression of CD4, MHC class I, CD18 or CD29.

Immunodiagnosis of feline immunodeficiency virus infection using recombinant viral p17 and p24.

The coding sequences of p17 and p24 of the Glasgow-8 strain of feline immunodeficiency virus (FIV) were amplified using the polymerase chain reaction and cloned into plasmid vectors. The predicted amino-acid sequences of FIV/Glasgow-8 p17 and p24 were compared with those of the Petaluma and PPR isolates of FIV. As seen with other retroviruses, these gag gene products are highly conserved, indicating that the protein products would be suitable antigens to detect anti-FIV antibodies in an immunoassay. Both p17 and p24 were stably expressed in Escherichia coli as fusion proteins with glutathione S transferase. A pure preparation of each fusion protein was obtained from induced bacterial lysates by affinity chromatography using glutathione-agarose beads. These recombinant proteins were used in an enzyme-linked immunosorbent assay to detect antibodies directed against FIV p17 and p24 in cat sera. This assay allows the identification of seropositive cats following infection with FIV and has greater sensitivity and specificity than a currently available immunodiagnostic test.

The generation of monoclonal antibodies recognising novel epitopes by immunisation with solid matrix antigen-antibody complexes reveals a polymorphic determinant on feline CD4.

Monoclonal antibodies were generated against the feline homologue of CD4 (fCD4) by immunisation of mice with solid matrix antigen-antibody complexes of monoclonal antibody Fel7 (anti-fCD4) and formalin-fixed Staphylococcus A (SMAA-fCD4). The resulting fusion produced nine monoclonal antibodies each of which recognised a major population of feline lymphocytes and which immunoprecipitated a 55 kDa ligand from the feline T lymphosarcoma cell line 3201. Epitope mapping of the antibodies against soluble fCD4 by surface plasmon resonance indicated that the antibodies recognised five separate epitopes distinct from that defined by the Fel7 antibody used to prepare the SMAA-fCD4. These data demonstrate that SMAA complexes are an efficient means of generating monoclonal antibodies recognising novel epitopes on an antigen. One monoclonal antibody (vpg39) recognised an epitope that was expressed variably between cats, being either present or completely absent. Analysis of peripheral blood lymphocytes from specific pathogen free cats suggested that failure to react with the vpg39 antibody was an inherited trait.

Involvement of gag- and env-specific cytotoxic T lymphocytes in protective immunity to feline immunodeficiency virus.

Definition of the immunological mechanisms involved in protective immunity against lentiviral infections is crucial to the development of an effective vaccine. The induction of gag- and env-specific cell-mediated immune responses was studied in cats following vaccination with whole inactivated feline immunodeficiency virus (FIV). Cats were immunized by inoculation with three doses of paraformaldehyde-inactivated FIV, derived from the feline lymphoid cell line, FL-4, which is persistently infected with the Petaluma isolate of FIV. Autologous or allogeneic skin fibroblasts either infected with recombinant FIV gag- or env-vaccinia virus or pulsed with FIV env peptides were used as targets in chromium-51 release assays. Effector cells were fresh peripheral blood mononuclear cells. Following the third immunization, all vaccinated cats, but none of the control cats immunized with adjuvant alone, had detectable FIV env-specific lymphocytotoxicity in their peripheral blood. Two cats also exhibited gag-specific activity. There was no recognition of either allogeneic skin fibroblasts infected with recombinant vaccinia virus or autologous target cells infected with wild-type vaccinia virus, indicating the specificity and MHC-restricted nature of the response. Vaccinated cats, but not control cats, were protected from challenge with the homologous Petaluma isolate of FIV. Partial epitope mapping of the env-specific cytotoxic response was performed using overlapping 10-amino acid peptides from the env V3 domain of FIV. This response appeared to be directed at env peptide 1 (RAISSWKQRN) and env peptide 3 (QRNRWEWRPD), which lie adjacent to a beta-turn within the V3 domain.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparative efficiency of feline immunodeficiency virus infection by DNA inoculation.

Direct inoculation of genetic material in DNA form is a novel approach to vaccination that has proved efficacious for a number of viral agents. We are interested in the potential of this approach for the delivery of vaccines based on attenuated or replication-defective retroviruses. Toward this goal, we tested the effect of intramuscular inoculation of a plasmid containing the entire genome of feline immunodeficiency virus (FIV-Petaluma, F14 clone). DNA delivery was compared with intramuscular or intraperitoneal inoculation of virus reconstituted from the same molecular clone. The outcome was monitored by serological analysis and quantitative virus load determination over a 31-week period. DNA inoculation was found to be a reliable means of infection, although seroconversion and the rise in PBMC virus load were delayed relative to intramuscular or intraperitoneal inoculation of virus. At 31 weeks, similar levels of proviral DNA were detected in central lymphoid tissue of all infected animals. In conclusion, DNA inoculation of proviral DNA will be of use as a novel method of cell-free virus challenge and may have further potential for the delivery of lentiviral vaccines.