Raised high-sensitivity C-reactive protein and cognitive impairment among African stroke survivors within the first three months following stroke.

Stroke remains a major factor causing death and disabilities such as cognitive impairment. There is conflicting evidence on the role and dynamics of high sensitivity C-reactive protein (hsCRP), an acute phase pro-inflammatory protein, in post-stroke cognitive impairment. This study evaluated cognitive impairment and examined its relationship with serum hsCRP in the first three months following stroke. Cognition was assessed using Montreal Cognitive Assessment test, while serum hsCRP concentrations were assessed using enzyme link immunosorbent assay kit. Data were processed using SPSS Statistics version 20.0. Sixty subjects, comprising of 30 stroke patients and 30 healthy subjects, matched for age, sex and level of education were studied. Cognitive impairment was observed among the stroke patients, while the healthy subjects showed normal cognitive function; and the difference in the cognitive scores of the two groups was highly significant (P = 0.001). There was higher prevalence of cognitive impairment among the stroke survivors compared to the non-stroke subjects. Serum hsCRP was significantly higher among the stroke survivors compared to the healthy subjects (P = 0.001). The high hsCRP level correlates well with duration of stroke and working memory domain of cognition. The data revealed a high prevalence of cognitive impairment and concurrent high serum hsCRP levels among stroke survivors in the first three months following stroke, in contrast with normal subjects. The high hsCRP level correlates with duration of stroke and working memory domain of cognition. The data suggest a role for serum hsCRP and inflammation in the development of post-stroke cognitive impairment.

Tissue responses of Clarias gariepinus (Catfish) to experimental Eimeria subepithelialis infection.

Coccidial infection is a common feature in most African fishes. As a result of the chronic nature of the disease in fish, mortality is gradual (Kim and Paperna, 1993a) and is often overlooked in most farms, with losses becoming evident only at the end of the production cycle. This study evaluates the tissue responses of Clarias gariepinus (Catfish) in an experimental infection with Eimeria subepithelialis using 200 laboratory-bred Juveniles. Four groups (A, B, C and D) of 50 Juveniles each were preconditioned for 2 weeks. Groups A and B were infected per os with 200 E. subepithelialis sporocysts per juvenile, while groups C and D served as uninfected controls. At the onset of demonstrable oocysts in liver and spleen tissues, groups B and C were treated for a week in Amprolium(R) dip (0.6 mg/L) at the rate of 1 h a day. Five fish from each group were culled at intervals of 3 days to study the tissue responses to infection. At gross pathological level, intestinal and testicular congestion, splenomegaly and hepatomegaly were the common features of the infection. Histological lesions in the infected and treated group (group B) were confined to the small intestine while extra-intestinal lesions were seen in the infected and untreated fish (group A). The presence of pathological lesions in tissues, following experimental infection of C. gariepinus with E. subepithelialis sporocysts, indicated that the parasite is pathogenic to the catfish. Contrary to coccidiosis of terrestrial animals, sporulation of oocysts in piscine coccidiosis appeared to occur endogenously within the host. The use of Amprolium in the control of piscine coccidiosis is effective only when used early in the course of the infection, prior to onset of clinical signs. Proper certification of brooder and replacement stock, improved plane of nutrition and adequate stocking density are recommended aquacultural practices that may minimize the incidence of visceral coccidiosis in cultured fish.

Rabies in apparently healthy dogs: histological and immunohistochemical studies.

A slaughterhouse survey for rabies virus infection among apparently healthy dogs slaughtered for human consumption was carried out in Maiduguri, Nigeria. Formalin-fixed and paraffin-embedded tissues (salivary gland, hippocampus, cerebrum, medulla, and trigeminal ganglion) were obtained from a total of 52 head samples from slaughtered dogs. The paraffin-embedded tissues were analysed histologically using the haematoxylin and eosin (H&E) method for the presence of inclusion bodies and histochemically by streptavidin - biotin peroxidase staining method for detection of rabies virus antigens. Prior to fixation of tissue, impression smears were made from the hippocampus and stained by Sellers method to detect the presence of Negri bodies. Rabies virus antigen was detected in tissues from 16 (31% ) of the 52 dog heads. Histological diagnosis by H&E revealed various degrees of inflammatory changes in the salivary gland and brain tissues with few Negri bodies from 10 (19% ) of the 52 dogs tested. However, all tissues positive by H&E were also positive by immunoperoxidase method using the streptavidin- biotin peroxidase staining procedure. Ten (30% ) of the 33 male and 6 (32% ) of the 19 female dogs tested were positive for presence of rabies virus antigen. There was no significant difference between sexes in relation to rabies virus infection. The application of immunoperoxidase staining technique in the localization of rabies virus antigen in the submaxillary salivary gland was more sensitive (based on the relative number of positive tissues) when compared with the application of the method to other organs. Apparently healthy dogs may be important in the epidemiology and control of rabies in this environment.

Preliminary studies on the use of solid-phase immunosorbent techniques for the rapid detection of Wesselsbron virus (WSLV) IgM by haemagglutination-inhibition.

Serum samples from 446 randomly selected persons belonging to different age groups and locations in Nigeria were tested for the presence of WSLV IgM using the flavivirus haemagglutination-inhibition (HI) test adopted to the solid-phase immunosorbent technique (SPIT). 61 (14%) persons had IgM to WSLV only, while 9 (2%) persons had heterologous IgM to WSLV and two other flaviviruses, namely yellow fever and Uganda S viruses. There was a high prevalence of IgM in people of younger age groups than those in older groups. The majority of the IgM positive sera (67 (96%) of the 70 positive sera reacted to high titres (>21:80). With the conventional HI tests, 314 (70%) of the total sera tested had HI antibodies to one or more flaviviruses (yellow fever, West Nile, Potiskum, Zika and Uganda S) out of which 305/314 (97%) had antibodies to 3 or more flaviviruses used in the tests. Although SPIT may not be as sensitive as the conventional HI test, it was found to be more specific and could be adopted for the detection of early WSLV infections in flavivirus hyperendemic environments.

Antigenic relatedness of selected flaviviruses: study with homologous and heterologous immune mouse ascitic fluids

A relacao antigenica de 9 Flavivirus, febre amarela (YF), Wesselsbron (WSL), Uganda S (UGS), Potiskum (POT), West Nile (WN), Banzi (BAN), Zika (ZK), Dengue tipo 1 (DEN-1) e Dengue tipo 2 (DEN-2), foi avaliada por reacao de inibicao da hemaglutinacao cruzada (cross-HI) e reacao de fixacao do complemento cruzada (Cross-CF) entre cada um dos virus e seu fluido ascitico homologo em camundongos. Medias de titulos foram calculadas usando os titulos heterologos e homologos. Reacoes cruzadas CF revelaram maiores variacoes antigenicas entre virus do que reacoes cruzadas HI. Nao houve variacao antigenica significativa entre virus WSL, POT e YF usando cada um dos metodos. Todavia, diferencas definidas da antigenicidade foram observadas entre eles e os virus UGS, BAN e ZK. Nao existiram diferencas significativas entre UGS, BANe ZK ou entre DEN-1 e DEN-2. A relacao sorologica entre Flavivirus e importante para se estabelecer o diagnostico e a epidemiologia destas infeccoes na Africa

Antigenic relatedness of selected flaviviruses: study with homologous and heterologous immune mouse ascitic fluids.

The antigenic relationship of 9 flaviviruses, Yellow fever (YF), Wesselsbron (WSL), Uganda S (UGS), Potiskum (POT), West Nile (WN), Banzi (BAN), Zika (ZK), Dengue type 1 (DEN-1) and Dengue type 2 (DEN-2), was assessed by cross-haemagglutination-inhibition (Cross-HI) and cross-complement fixation (Cross-CF) reactions between each of the viruses and their homologous immune mouse ascitic fluids. Titre ratios were calculated using the heterologous and homologous titres. Cross-CF reactions revealed wider antigenic variations among viruses than Cross-HI reactions. There was no significant antigenic variation between WSL, POT and YF viruses using either of those methods. However, definite differences in antigenicity were observed between them and UGS, BAN and ZK viruses. There were no significant differences between UGS, BAN and ZK or between DEN-1 and DEN-2. The serological relationship among flaviviruses is important in establishing diagnosis and epidemiology of these infections in Africa.

Wesselsbron virus antibody in domestic animals in Nigeria: retrospective and prospective studies.

Retrospective and prospective serological surveys to determine the prevalence of Wesslsbron (WSL) virus infections in animal populations were carried out in different vegetational zones in Nigeria. Sera from 1,492 animals comprising 292 camels, 81 horses, 4 donkeys, 320 cattle, 235 sheep, 260 goats, 114 pigs, 101 dogs and 85 domestic fowls were assayed by haemagglutination-inhibition (HI) test for presence of antibodies to WSL virus and other flavivirus antigens: Yellow Fever (YF), Potiskum (POT), Banzi (BAN), Uganda S (UGS) and West Nile (WN) viruses. Four hundred and eighty one (32%) of the total sera tested were positive for the presence of flavivirus antibodies. The prevalence rates among animals varied with species and vegetational zones of the country. The highest prevalence was noted in animals from a swamp forest zone and was higher among camels, horses, donkeys and sheep when compared with goats, pigs and fowls in different zones. Although monotypic reactions with WSL virus antigen were observed in positive sera, the majority of the WSL virus positive sera cross-reacted with more than two other flavivirus antigens. Serological cross-reactions were most extensive in WSL virus positive horse sera. A ten month sentinel survey among 28 cattle, 68 sheep and 30 goats revealed considerable activity of WSL virus in Nigeria. Of these, 11 cattle and 12 sheep showed antibody conversion to WSL virus antigen. None of the goats seroconverted. Although, there are no records of outbreak of WSL disease in Nigeria, this study revealed that WSL virus is actively circulating among livestock populations in this environment. Flavivirus nucleotide data are needed for final determination of genetic relatedness in this group of viruses.

Isolation and identification of African horse sickness virus during an outbreak in Lagos, Nigeria.

An outbreak of African horse sickness involving two horse stables in Lagos, Nigeria, was investigated. Inoculation of blood from infected horses into suckling albino mice resulted in isolation of a virus which was identified as African horse sickness virus by the complement fixation test. The clinical, pathological and epizootiological findings (reported elsewhere) were consistent with African horse sickness. Potential threats of the epidemic to international horse trade are briefly highlighted.

Virological and immunological studies of Wesselsbron virus in experimentally infected red Sokoto (Maradi) goats.

Red Sokoto goats aged four to five months were experimentally infected with the Nigerian strain of Wesselsbron virus. Viraemia commenced 24-72 hours after infection and lasted for 3-4 days. A febrile reaction which was mostly biphasic coincided with viraemia. A 50% mortality rate was observed among infected animals. The virus was re-isolated in mice from almost every tissue (liver, spleen, lungs, brain, kidney, adrenal, lymph node and heart) obtained from dead goats. Complement fixing antigens were detected in the tissues of dead goats, the titre of which correlated positively with the infectivity titre. All infected animals developed complement-fixing and haemagglutination inhibiting antibodies to Wesselsbron virus. However, neutralizing antibody was detected only in goats that survived the infection.

Haemagglutination-inhibiting antibodies against African horse sickness virus in domestic animals in Nigeria.

A sero-epidemiological survey of African horse sickness (AHS) virus in 261 animals which included 96 camels, 81 horses, 80 dogs and 4 donkeys was carried out in Nigeria. The animals had no history of vaccination against AHS. Sera were tested by the haemagglutination-inhibition (HI) test for the presence of antibody against AHS virus. Of these, 77 (95.1%) horse, 4 (100%) donkey, 10 (10.4%) camel and 28 (35%) dog sera samples tested were recorded as positive. The prevalence of antibody in samples taken from horses in different regions was similar. The prevalence of antibody to AHS virus detected in camels and dogs suggests that these animals are possible reservoirs of the virus. This may have an influence upon the epidemiology of the disease in Africa as a whole.

Wesselsbron virus haemagglutination: studies with erythrocytes of various animal species at different pH and temperatures.

The haemagglutinating (HA) properties of the Nigerian strain of Wesselsbron virus have been investigated using erythrocytes from a wide range of animals. The results showed that Wesselsbron virus possesses HA activity when extracted using the sucrose and acetone method. The erythrocytes of goose, horse, donkey, pig, cattle, sheep, goat, monkey, man, rabbit, rat, guinea pig and chicken were agglutinated by Wesselsbron virus at different pH values (5.75-7.0) and temperatures of 4 degrees C, room (25 +/- 2 degrees C) and 37 degrees C. The ability to haemagglutinate fell as pH increased, but the effect of incubation at different temperature was not marked. However, under the conditions of the experiment HA pattern was clearest at 37 degrees C. High HA titres (> or = 1:16) were consistently obtained using goose, horse, donkey and human erythrocytes at different temperatures.

Sero-epidemiological studies of respiratory syncytial and adenoviruses in children in Ibadan, Nigeria, 1985-1988.

Retrospective and prospective serological surveys to determine the prevalence of respiratory syncytial virus (RSV) and adenovirus (ADV) infections in children with respiratory diseases were carried out from 1985 to 1988 at the University College Hospital, Ibadan, Nigeria. 306 sera from subjects between 3 months and 12 years old were assayed by complement fixation test for antibodies to both viruses. Second samples were available from 42 of the subjects for antibody conversion testing. The rate varied with age, period of the year and virus. Overall prevalences of 23.5% and 18.3% were obtained for RSV and ADV respectively. 2.6% of the subjects had antibodies to both viruses. Among 42 paired samples tested, 61.9% and 33.3% showed positive antibody conversion to RSV and ADV respectively. Although there was evidence of active circulation of both viruses throughout the year, infection with RSV was higher from September to January, while ADV infection was significantly higher during February and March. Antibody prevalence to both viruses increased with age up to a peak of 39.1% for RSV in children 5-6 years old and 32% for ADV in children 3-4 years old. None of the subjects aged 10 years and above was positive for both viruses. Both RSV and ADV are important agents of acute respiratory infection in children in Nigeria.

Complement fixing antibodies against selected viruses in diabetic patients and non-diabetic control subjects in Ibadan, Nigeria.

Sera of forty insulin-treated Nigerian diabetics attending the outpatients clinic of the University College Hospital (U.C.H.), Ibadan, and an equal number of non-diabetic control subjects matched for age, sex and social status were tested for presence of complement fixing (CF) antibodies against five viruses: Coxsackie A and B1, mumps rubella and enterovirus group antigen. Antibody levels to Coxsackie B1, mumps, rubella and enterovirus did not show any significant difference between the two groups (P > 0.05). The serum levels of antibody to Coxsackie A virus were significantly higher in non-diabetic controls than in the diabetics (P < 0.05). Previous exposure to these viruses may not be a significant factor in the aetiology of insulin dependent diabetes mellitus in this environment.

Prevalence of complement-fixing antibody to the African horse sickness virus in domestic animals in Nigeria.

The occurrence of antibodies against the African horse sickness virus was investigated in 246 domestic animals (horses, donkeys, camels, dogs) in various regions of Nigeria by means of the complement-fixing rate. 34% of the sera tested were positive: 75% in donkeys, 68% in horses, 19% in camels, and 9% in dogs. Among the horses, those of 6 to 15 years of age had higher than average prevalence rates than the other age groups. Stallions from the northern regions had higher prevalence rates than mares generally and stallions from other regions. These findings are important for the epidemiology of the African horse sickness in Nigeria just as the complement-fixing rates are in camels and dogs for the epidemiology of this sickness in the whole of Africa.

Haemagglutination-inhibiting antibodies against influenza A and B in human sera collected from five ecological zones in Nigeria.

The prevalence of antibodies to the haemagglutinins of two influenza A subtype, H1N1 and H3N2 and influenza B in sera collected from 1986 to 1988 from persons of different ages and from 10 locations in 5 ecological zones of Nigeria was determined. The levels of influenza antibodies in the sera varies with age and ecological zones of the country. A total of 1,022 sera were tested, of which 732 (71.6%) were positive for influenza antibodies. The prevalence of antibodies at titre 1:10 varied between 31.1% in the derived savannah and 94.4% in the swamp forest. The prevalence in the other zones were: rain forest 63.9%, guinea savannah 86.0% and 78.0% in sudan savannah. Reactors with the two influenza A subtypes antigens were more than reactors with influenza B antigens in the country. Antibody levels to influenza A subtypes varied between and within zones. Although there was no significant difference a (P greater than 0.05) in the overall prevalence of antibodies to the two subtypes, more sera had haemagglutination-inhibiting antibody to H1N1 subtype than H3N2 subtype in all the zones except in the rain forest. Prevalence of antibodies to influenza viruses increased with age in all the zones. Overcrowding in big cities and dry, dusty harmattan weather of the northern parts of the country are considered as possible risk factors in the epidemiology of influenza in Nigeria.

Growth of Igbo-Ora virus in some tissue cultures.

VERO, MRC5, MDCK, and MA104 cells were tested for their ability to support the growth of Igbo-Ora virus. In VERO and MRC5 cell cultures the virus replicated to high titres causing apparent cytopathic effects (CPE) (cell rounding and complete lysis) and formation of complement fixing antigens. The virus grew to lower infectious titre in MDCK and MA104 cell cultures in which CPE was limited to cell rounding only.

Seroepidemiological survey for yellow fever antibodies in domestic animals.

A total of 192 out of 300 serum samples from camel, cattle, sheep and goats tested for yellow fever virus antibody by the counterimmunoelectrophoresis were found positive. This test was confirmed by the single radial haemolysis and serum neutralization tests. Twenty-one and 36 sera were positive for specific yellow fever virus antibodies by the single radial haemolysis and serum neutralization tests respectively. The possible role of these animals in the epidemiology of yellow fever is discussed.

Cytomegalovirus infection among tuberculosis patients in a chest hospital in Nigeria.

A serological study was carried out in Ibadan, Nigeria to determine the prevalence of inapparent infection with cytomegalovirus among tuberculosis patients and its relation to the epidemiology of the virus in this environment. A total of 360 sera from 161 tuberculosis patients, 89 patients other than tuberculosis and 110 healthy voluntary blood donors were examined for antibody to cytomegalovirus by the complement fixation test. One hundred and forty-one (87.6%) of the tuberculosis patients, 45 (50.6%) patients other than tuberculosis and 60 (54.6%) healthy blood donors had a complement fixing antibody to cytomegalovirus. Although the total prevalence (68.3%) of complement fixing antibody against cytomegalovirus in all the groups is high, it is higher among the tuberculosis patients than the other groups in the same environment. This shows that tuberculosis which is still a major health problem in Nigeria may be playing a significant role in the spread of cytomegalovirus in the country.

Haemagglutination-inhibiting (HI) antibodies against strains of influenza A virus in horse and pig sera in Nigeria.

Sera from horses and pigs obtained from Lagos and Ibadan respectively were examined for haemagglutination-inhibiting (HI) antibodies to two strains each of H3N2 and H1N1 subtypes of influenza A virus. More horse sera had HI antibodies to the H3N2 than the H1N1 strains while pig sera reacted almost equally with strains of both subtypes. All the horse sera had HI antibodies to the two strains of H3N2 subtype (A/Mississippi/1/85 and A/Leningrad/360/86), while 87% and 14% of the horses examined were positive to A/Taiwan/1/86 and A/Chile/1/83. On the other hand HI antibody prevalence to the two subtypes in pigs are as follows, for H3N2 A/Mississippi/1/85 (86%), A/Victoria/3/75 (94%); for H1N1 A/Chile/1/83 (87%) and A/Taiwan 1/86 (79%). Analysis of the data by the Chi-square test showed significant difference between the prevalence of HI antibodies to the influenza A virus strains in horse sera examined while there was no significant difference between HI antibody prevalence to the four strains in pigs. The study shows that horses and pigs circulate influenza A virus in Nigeria and may serve as origin of human epidemics.

Yellow fever haemagglutination-inhibiting, neutralising and IgM antibodies in vaccinated and unvaccinated residents of Ibadan, Nigeria.

A survey for yellow fever virus haemagglutination inhibiting (HI) and neutralising (N) and IgM antibodies was carried out in unvaccinated people in Ibadan and in those immunised with the yellow fever 17-D vaccine. A total of 207 people were tested for HI antibody to yellow fever and two other flaviviruses namely: Wesselsbron and Uganda S. viruses. Prevalence of HI antibody to each flavivirus antigen was as follows: Yellow fever 26%, Wesselsbron 18% and Uganda S 33%. Of the 207 people, 37 (18%) had yellow fever N antibody. There was a higher prevalence of N antibody to yellow fever virus in adults than children. Twenty-one people vaccinated with 17-D yellow fever vaccine donated post-vaccination sera; 10 (48%) had no prevaccination HI antibody, 7 (33%) had HI antibody to one flavivirus and 4 (19%) to two or more flaviviruses. Ninety percent of seronegative people and all those with prevaccination flavivirus antibodies developed HI or N antibody, following vaccination. A total of 58 unvaccinated people were tested for yellow fever IgM antibody by an enzyme linked immunosorbent assay, 2 (3%) were positive; suggesting that active yellow fever transmission was in progress at the time of survey.