Effects of Irrigation and Rainfall on the Population Dynamics of Rift Valley Fever and Other Arbovirus Mosquito Vectors in the Epidemic-Prone Tana River County, Kenya.

Rift Valley fever (RVF) is a mosquito-borne viral zoonosis that is found in most regions of sub-Saharan Africa, and it affects humans, livestock, and some wild ungulates. Outbreaks are precipitated by an abundance of mosquito vectors associated with heavy persistent rainfall with flooding. We determined the impact of flood-irrigation farming and the effect of environmental parameters on the ecology and densities of primary and secondary vectors of the RVF virus (RVFV) in an RVF-epidemic hotspot in the Tana River Basin, Kenya. Mosquito sampling was conducted in farms and villages (settlements) in an irrigated and a neighboring nonirrigated site (Murukani). Overall, a significantly higher number of mosquitoes were collected in farms in the irrigation scheme compared with villages in the same area (P < 0.001), or farms (P < 0.001), and villages (P = 0.03) in Murukani. In particular, key primary vectors of RVFV, Aedes mcintoshi Marks and Aedes ochraceous Theobald, were more prevalent in the farms compared with villages in the irrigation scheme (P = 0.001) both during the dry and the wet seasons. Similarly, there was a greater abundance of secondary vectors, particularly Culex univittatus Theobald and Culex pipiens (L.) in the irrigation scheme than in the Murukani area. Rainfall and humidity were positively correlated with mosquito densities, particularly the primary vectors. Adult floodwater mosquitoes and Mansonia spp. were collected indoors; immatures of Ae. mcintoshi and secondary vectors were collected in the irrigation drainage canals, whereas those of Ae. ochraceous and Aedes sudanensis Theobald were missing from these water bodies. In conclusion, irrigation in RVF endemic areas provides conducive resting and breeding conditions for vectors of RVFV and other endemic arboviruses.

Neural Network Computer Analysis of Fetal Heart Rate.

> Objective: A nonsubjective evaluation of intrapartum fetal heart rate (FHR) with a neural network (NNW) computer system and its clinical application. Methods: Eight simple FHR data were input into the NNW computer after 16-step normalizations. The computer was composed of 40 units in the input layer, 30 in intermediate layer, and 3 in the output layer, and the probabilities to be normal, suspicious, and pathological were obtained at the output. Before use, the computer was trained 10,000 times by 50-min teacher FHR data of 20 cases with known outcomes. The trained NNW computer was tested by FHRs of another 29 cases. The outcome probabilities in 15 min were calculated every 5 min in another 10 cases, and the bar graphs of the probabilities were displayed in sequence in the trendgrams. Results: The trained NNW computer was 100% accurate in the internal check; in the external check 86% of the results were evaluated correctly with the cardiotocogram, Apgar score, and umbilical arterial pH of the 29 test cases. The FHR scores of our conventional computer FHR analysis were higher in the suspicious and pathological groups than the normal group, and the fetal distress index was high in the pathological group. The trendgrams were simply accurate in typically normal or abnormal cases, transitory abnormal probabilities were shown in intermediate cases, and mixed suspicious and pathological probabilities suggested pathological outcome. Conclusions: The outcome probabilities and their trendgrams in the NNW FHR analysis are promising in objective decision making in the intrapartum stage.

Ultrasonographic findings in the periventricular region in premature newborns with antenatal periventricular leukomalacia.

Cranial ultrasonography was carried out at least three times a week during the first 16 days of life in all 53 premature newborns born within study period. If a cyst of more than three mm was detected in the periventricular region by fourteenth day of life, it was judged to be antenatal PVL. Periventricular echodensity was classified into mild, moderate or severe periventricular echodensity (PVE). Among 53 newborns, 11 babies (20.8%) were diagnosed as having antenatal PVL. Cysts were observed in the first two days in 9 cases (81.8%) out of 11 babies, and in bilateral periventricular regions in 8 cases (72.7%) out of 11 babies. All 3 babies with severe PVE in the periventricular region had PVL at the time of diagnosis or developed PVL shortely after severe PVE was detected.

Clinical features of and cardiotocographic findings for premature infants with antenatal periventricular leukomalacia.

OBJECTIVE: To clarify the clinical features of and cardiotocographic findings for premature infants with antenatal periventricular leukomalacia (PVL). METHODS: Antenatal PVL was judged to be present if a cyst greater than 3 mm in largest diameter was detected in the periventricular region by the 14th day of life on cranial ultrasonography. The clinical features of and cardiotocographic findings for 12 premature infants with antenatal PVL born within 1 year were compared with those of 12 infants chosen as control group matched in gestational age at birth from the premature infants without antenatal PVL born within the study period. RESULTS: Abnormalities of the umbilical cord such as coiling, excessive torsion and membrane insertion were observed more frequently for infants with antenatal PVL (58.3%) than for control infants (16.7%) (P<0.05). Frequent moderate variable deceleration on the fetal cardiogram was also observed more frequently for infants with antenatal PVL (80.0%) than for control infants (27.3%) (P<0.05). CONCLUSION: Abnormalities of the umbilical cord and frequent moderate variable deceleration on fetal cardiotocogram appear to be causes of antenatal PVL in premature infants.

Hysterotomy and selective delivery of an intrauterine dead fetus to prevent intrauterine death or brain damage of the surviving fetus in monochorionic twin pregnancy.

When pregnancy is continued after death of one fetus in monochorionic twin pregnancy, the surviving fetus sometimes exhibits intrauterine death or brain damage. Hysterotomy and selective delivery of an intrauterine dead fetus was performed in order to prevent intrauterine death or brain damage of the surviving fetus at 24 weeks' gestation in a monochorionic twin pregnancy. The healthy baby except for immaturity was born at 30 weeks' gestation, and exhibited no brain damage postnatally. When one fetus has died in utero before maturity of surviving fetus, hurried selective delivery of dead fetus should be one of the useful treatments to prevent intrauterine death or brain damage of the surviving fetus in monochorionic twin pregnancy.

Prenatal diagnosis of congenital myotonic dystrophy in two Japanese families: direct mutation analysis by a non-radioisotope PCR method and haplotype analysis with flanking DNA markers.

The prenatal diagnosis of congenital myotonic dystrophy in two Japanese families was reported. The CTG repeat size in the myotonin/protein kinase gene was determined by a nonradioisotope PCR method. Polymorphisms of the DNA markers (ApoCII, X75b-VSSM and KLK-1) flanking the CTG repeat were analyzed from normal Japanese and were used to determine the risk haplotype. Two pregnant women with myotonic dystrophy requested prenatal diagnosis. The first case was diagnosed as having myotonic dystrophy at 36 weeks of pregnancy. The CTG repeat size in the cord blood from the fetus was not expanded and the risk for the disease was judged to be low by haplotype analysis with the X75b-VSSM marker. In the second case, the chorionic villus was sampled in the pregnant mother who had already had two children with congenital myotonic dystrophy. The small expanded allele (36 repeats) from the mother and a normal allele from the father were detected in the chorionic villus. The risk for the disease was not determined by haplotype analysis with ApoCII and X75b-VSSM, only being judged as low by haplotype analysis with KLK-1 in the second case. These babies from two families were born and developed normally. DNA diagnosis for direct CTG repeat expansion combined with haplotype analysis has been useful for pregnant women with myotonic dystrophy who are at high risk of having severely affected babies.

The movements of fetuses with congenital myotonic dystrophy in utero.

The movements in two fetuses with congenital myotonic dystrophy were recorded on fetal actocardiograms. The two fetuses showed gross movements associated with FHR accelerations as normal fetus. One of them showed swallowing on amniofetogram, and hiccuping on fetal actocardiogram. Both, however, were extremely hypotonic and neither displayed any gross movement, respiratory movement or swallowing postnatally. Intubation and nasal feeding were required for a long period of time after birth in both cases. The buoyancy of amniotic fluid may help the affected fetus to make gross movement in utero.

[Diagnosis of fetal heart rate without referring to uterine contraction].

The purpose of this study is to evaluate intrapartum fetal condition only with reference to fetal heart rate (FHR) change. Sixty-five cases who had no severe complications were examined at 36 weeks to 42 weeks of gestation. Major cardiotocographic abnormalities were baseline bradycardia and severe variable deceleration. Late deceleration was not observed. The conventional program of automatic FHR diagnosis and a new computer program excluding uterine contraction (UC) algorithm were used. Digitalized FHR and UC data stored in a floppy disk were reproduced and analysed by either of the programs with and without UC. FHR scores and FD index obtained by the 2 programs were highly correlated with each other. Both the FHR score and FD index showed a correlation to PO2, PCO2, BE and pH of umbilical artery blood. There were no significant differences between the correlation coefficients for the 2 methods. The sensitivity of the FD index which predicted a pH of umbilical artery blood lower than 7.25 was 86.4% in both groups. And the specificity was 88.4% in the results obtained with UC and 90.7% without UC. There was no significant difference in sensitivity or specificity in both groups.